ASTR_1220_ExpertTA

3/1/24, 6:38 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51094 3/24 the average distance between the Earth and the Sun the average distance between the Earth and the Sun Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:37 PM the average distance between the Earth and the Sun Problem 5: Written in correct scientific notation, the number 13.8 billion becomes: Grade = 100% Correct Answer Student Final Submission Feedback 1.38 x 10 10 1.38 x 10 10 Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:37 PM 1.38 x 10 10

3/1/24, 6:38 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51094 6/24 Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:38 PM Earths = Problem 10: The fastest human spaceship leaving the solar system is Voyager 1, which is traveling at 61,146 kilometers per hour. Imagine it is traveling to a star system 8.9 light-years away. Calculate how long, in years, it will take for Voyager 1 to arrive. Grade = 50% Correct Answer Student Final Submission Feedback t = t = 157075.53 t = Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 50 % Student Grade = 100 - 0 - 50 = 50% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:38 PM t = 1.659 * 10 5 t = 2 Jan 31, 2024 6:39 PM t = 166032.36 t = 3 Jan 31, 2024 6:39 PM t = 157075.53 t = Problem 11: n January 2022, the New Horizons spacecraft reached a distance of 53 astronomical units (AUs) from the Earth. 34.44 1.571 × 10 5 1.571 × 10 5 1.659 × 10 5 1.660 × 10 5 1.571 × 10 5

3/1/24, 6:38 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51094 9/24 Problem 14: Ranking Put the astronomical locations in order of increasing distance from us; start with the closest and end up with the most distant. Please use the drag-and-drop environment to label the missing parts of the figure from closeset to farthest. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:40 PM Problem 15: Light-Years and Light Travel Time Because cosmic distances are so vast, astronomers use light-years as their unit of distance. One light-year is defined as _______________________. The nearest star is a little more than ____ light-years away from us. When we see light from a galaxy 2 million light-years away, it has taken _______________ to reach us. Light from the Sun takes ___________ to reach us. Moon Sun Pluto Center of the Milky Way Galaxy The Andromeda Galaxy Moon Sun Pluto Center of the Milky Way Galaxy The Andromeda Galaxy Moon Sun Pluto Center of the Milky Way Galaxy The Andromeda Galaxy

3/1/24, 6:38 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51094 12/24 Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:41 PM Problem 18: By looking billions of light-years out into space, astronomers are actually seeing billions of years into the past. Grade = 100% Correct Answer Student Final Submission Feedback TRUE TRUE Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. About 100 thousand light-years 13.8 billion years 10 7 sec 1 light-year 13.8 billion light-years About 100 thousand light-years 13.8 billion years 10 7 sec 1 light-year 13.8 billion light-years About 100 thousand light-years 9.5 trillion km, or 6 trillion miles 300 thousand km/s, or 186 thousand mi/s 13.8 billion years 150 million km, or 93 million mi 365.25 days, or 3 x 10 7 sec 1 light-year 13.8 billion light-years

3/1/24, 6:38 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51094 15/24 Put the following bands into order by wavelength, from shortest to longest. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:44 PM Problem 23: Ranking Please put the following bands of the electromagnetic spectrum in order of their photon energy, from least to greatest. Please use the drag-and-drop environment to label the missing parts of the figure from least to greatest photon energy Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Gamma rays Ultraviolet Visible Light Infrared Radio Gamma rays Ultraviolet Visible Light Infrared Radio Gamma rays Ultraviolet Visible Light Infrared Radio radio infrared visible ultraviolet x ray gamma ray radio infrared visible ultraviolet x ray gamma ray

3/1/24, 6:38 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51094 18/24 Please use the drag-and-drop environment to label the missing parts of the figure from longest to shortest. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:44 PM Problem 27: Ranking Arrange the waves below in order of wavelength, shortest to longest. Please use the drag-and-drop environment to label the missing parts of the figure from shortest to longest. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Microwave Red Blue Ultraviolet Gamma Ray Microwave Red Blue Ultraviolet Gamma Ray Microwave Red Blue Ultraviolet Gamma Ray

3/1/24, 6:38 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51094 21/24 Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:45 PM Problem 30: Sorting Categorize each of the spectra below.

3/1/24, 6:38 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51094 22/24 Please use the drag-and-drop environment to label the missing parts of the figure. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:46 PM

3/1/24, 6:38 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51094 23/24 Problem 31: Ranking The figure below illustrates an energy level diagram for hydrogen, with several electron transitions indicated by arrows. Arrange the letters corresponding to each transition in order of the emitted energy, highest to lowest. (Assume the spacing of the lines is an accurate indicator of their relative energy levels.) Please use the drag-and-drop environment to label the missing parts of the figure from highest to lowest Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:46 PM Problem 32: Labeling A F D E C B A F D E C B A F D E C B

3/1/24, 6:38 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51094 24/24 An object’s spectrum spans more than just visible light. An object like Mars, for example, has spectral features in the ultraviolet and infrared regions as well. Let’s try to predict what those features should look like. Match the description of what contributes to each region of Mars’ spectrum with what that region of Mars’ spectrum ought to look like from our perspective on Earth. Please use the diagram below to place choices in their corresponding buckets. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Jan 31, 2024 6:46 PM All content © 2024 Expert TA, LLC Continuous spectrum Absorption spectrum Emission spectrum Continuous spectrum Absorption spectrum Emission spectrum Continuous spectrum Absorption spectrum Emission spectrum Continuous spectrum Absorption spectrum Emission spectrum Continuous spectrum Absorption spectrum Emission spectrum Continuous spectrum Absorption spectrum Emission spectrum Continuous spectrum Absorption spectrum Emission spectrum Continuous spectrum Absorption spectrum Emission spectrum Continuous spectrum Absorption spectrum Emission spectrum

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 1/21 ASTR 1220 (Spring 2024) Pryal Homework 3: Spectroscopy & Telescope Baiscs Kim, Mingyeong - yye5qg@virginia.edu Problem 1: You are alone in a large, completely dark auditorium on Earth. What kind of telescope should I use from the other side of the auditorium to detect the electromagnetic radiation emitted by your body? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback infrared infrared Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 4:34 PM infrared Problem 2: (In the absence of a strong magnetic field), what is the chief factor that determines what type of electromagnetic radiation objects give off: Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback their temperature their temperature Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 4:35 PM their temperature

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 2/21 Problem 3: Two stars are giving off electromagnetic radiation. The hotter star will: Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback all of these all of these Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 4:37 PM all of these Problem 4: Astronomers observe a typical star using a telescope and a spectrometer. They will see: Please select the best choice from the available options. Grade = 75% Correct Answer Student Final Submission Feedback more than one of these more than one of these Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 25 % Student Grade = 100 - 0 - 25 = 75% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 4:37 PM an absorption spectrum Note: Feedback not accessed. 2 Feb 01, 2024 4:38 PM more than one of these

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 3/21 Problem 5: Why do different types of atoms (elements) give off or absorb different spectral lines? Please select the best choice from the available options. Grade = 75% Correct Answer Student Final Submission Feedback because the spacing of the energy levels is different in different atoms because the spacing of the energy levels is different in different atoms Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 25 % Student Grade = 100 - 0 - 25 = 75% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 4:39 PM because some atoms do not have a ground state, while others have three or four 2 Feb 01, 2024 4:39 PM because the spacing of the energy levels is different in different atoms Problem 6: How do astronomers learn what elements are present in a given star? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback look at the absorption lines in its spectrum look at the absorption lines in its spectrum Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 4:40 PM look at the absorption lines in its spectrum

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 4/21 Problem 7: When a star or galaxy is moving away from us, we observe the Doppler effect by seeing the lines in its spectrum Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback redshifted (shifted toward the red end of the light spectrum) redshifted (shifted toward the red end of the light spectrum) Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 4:56 PM redshifted (shifted toward the red end of the light spectrum) Problem 8: The figure shown illustrates an emission spectrum from a source that is stationary with respect to the observer (you). Suppose the source was moving toward you at a high speed. Which of the spectra below would you expect the new observed spectrum to resemble? Grade = 100% Correct Answer Student Final Submission Feedback B B Correct! Grade Summary Deduction for Final Submission 0 %

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 5/21 Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 4:57 PM B Problem 9: A spectral line associated with a particular element is measured in the lab to be at a wavelength of 570.2 nm. An astronomer measures it in Star Y’s spectrum at a wavelength of 571.0 nm, and in Star Z’s spectrum at a wavelength of 570.6 nm. Which statement best describes what is happening? Grade = 100% Correct Answer Student Final Submission Feedback Both stars are moving away from us, with Star Y receding faster. Both stars are moving away from us, with Star Y receding faster. Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 4:58 PM Both stars are moving away from us, with Star Y receding faster. Problem 10: A star has a surface temperature of 9060 K. At what wavelength (in nanometers) will it give off maximum light? Grade = 100% Correct Answer Student Final Submission Feedback λ max = nm λ max = nm Correct! Grade Summary Deduction for Final Submission 0 % 319.9 320.0

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 6/21 Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 4:59 PM λ max = nm Problem 11: The emitted infrared radiation from a dwarf planet has a wavelength of maximum intensity at = 78000 nm. What is the temperature in Kelvin assuming it follows Wien's law? Grade = 100% Correct Answer Student Final Submission Feedback = = Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:00 PM = 320.0 λ max T T 37.15 K T 37.15 K T 37.15 K

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 7/21 Problem 12: The figure below shows a blackbody spectrum. Based on Wien’s Law, what temperature does this spectrum correspond to in Kelvins? Grade = 0% Give Up was accessed and a deduction for using the Give Up may have been applied. Correct Answer Student Final Submission Feedback T = K T = 2898/50 T = K Grade Summary Deduction for Final Submission 100 % Deductions for Incorrect Submissions, Hints and Feedback [?] 75 % Student Grade = 100 - 100 - 75 = 0% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:06 PM T = K 2 Feb 01, 2024 5:11 PM T = 2898/400 T = K 3 Feb 01, 2024 5:12 PM T = 2898/50 T = K Problem 13: Ranking Arrange the images of stars below in order of surface temperature, hottest to coolest. Please use the drag-and-drop environment to label the missing parts of the figure from hottest to coolest. Grade = 100% 5455 57.96 5796 7.245 57.96

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 8/21 Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:13 PM Problem 14: Ranking Suppose you observed five stars and obtained the following spectra. Using the drag-and-drop environment, arrange the spectra in order of surface temperature, from hottest to coolest. Grade = 100% Correct Answer Student Final Submission Feedback Correct!

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 9/21 Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:14 PM Problem 15: Blackbody Spectrum Use the following link to open the simulation in a new tab. Blackbody Spectrum . Follow the directions listed below, while making use of the simulation to find your answer(s). This simulator illustrates the blackbody spectrum for an object of a given temperature. Because stars closely resemble blackbodies, we can use a blackbody model to estimate stellar surface temperatures. Part (a) Which temperature most closely corresponds to a star whose spectrum peaks firmly in the violet region of the spectrum? Grade = 80% Correct Answer Student Final Submission Feedback 7300 K 7300 K Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 20 % Student Grade = 100 - 0 - 20 = 80% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:16 PM 8600 K 2 Feb 01, 2024 5:17 PM 7300 K Part (b) Which temperature most closely corresponds to a star whose spectrum peaks firmly in the red region of the spectrum? Grade = 100% Correct Answer Student Final Submission Feedback 4100 K 4100 K Correct!

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 10/21 Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:17 PM 4100 K Part (c) Which temperature most closely corresponds to a star whose spectrum peaks firmly in the ultraviolet region of the spectrum? Grade = 80% Correct Answer Student Final Submission Feedback 8600 K 8600 K Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 20 % Student Grade = 100 - 0 - 20 = 80% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:17 PM 3000 K 2 Feb 01, 2024 5:19 PM 8600 K Problem 16: Blackbody Spectrum Use the following link to open the simulation in a new tab. Blackbody Spectrum . Follow the directions listed below, while making use of the simulation to find your answer(s). This simulator illustrates the blackbody spectrum for an object of a given temperature. Because stars closely resemble blackbodies, we can use a blackbody model to estimate stellar surface temperatures. Which of the statements below accurately describes how the amount of RED light that Sirius A emits compares to the amount of RED light that a 4000 K star emits? Grade = 50% Correct Answer Student Final Submission Feedback Sirius A emits more UV light than red light, but still emits more red light than a 4000 K star. Sirius A emits more UV light than red light, but still emits more red light than a 4000 K star. Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 50 % Student Grade = 100 - 0 - 50 = 50% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:21 PM Sirius A emits more UV light than red light, but emits an equal amount of red light as a 4000 K star. 2 Feb 01, 2024 5:21 PM Sirius A emits more UV light than red light, and emits less red light than the 4000 K star. 3 Feb 01, 2024 5:25 PM Sirius A emits more UV light than red light, but still emits more red light than a 4000 K star.

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 11/21 Problem 17: The most important function of an astronomical telescope is to: Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback collect as much light as possible and bring it to a focus collect as much light as possible and bring it to a focus Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:25 PM collect as much light as possible and bring it to a focus Problem 18: The earliest telescopes used by astronomers were: Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback refractors refractors Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:26 PM refractors

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 12/21 Problem 19: When a knowledgeable amateur astronomer tells you that she has a 14-inch telescope, what does the number 14 refer to? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback the diameter of the primary lens or mirror the diameter of the primary lens or mirror Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:27 PM the diameter of the primary lens or mirror Problem 20: An astronomer is studying galaxies of stars that are very far away and thus look extremely faint (using visible light). What kind of telescope should she and her graduate students apply for time on? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback the telescope with the biggest aperture possible the telescope with the biggest aperture possible Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:28 PM the telescope with the biggest aperture possible

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 13/21 Problem 21: The largest visible-light telescopes in the world use what device to collect as much light as possible before the light is brought to a focus (to act as the "light bucket")? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback a mirror a mirror Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:28 PM a mirror Problem 22: A graduate student is trying to follow the weather on Jupiter for her PhD thesis. To see the big weather patterns in the upper atmosphere of the planet, she needs to have excellent resolution. What type of telescope would be best for her to use? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback a large reflector located in orbit above the Earth's atmosphere a large reflector located in orbit above the Earth's atmosphere Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:29 PM a large reflector located in orbit above the Earth's atmosphere

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 14/21 Problem 23: A very wealthy donor decides to give a large sum of money to your college or university to build the world's largest visible-light gathering telescope. From an astronomical perspective, where would be the best location to put such a telescope? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback on a tall, dry mountain peak on a tall, dry mountain peak Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:30 PM on a tall, dry mountain peak Problem 24: At the largest and most modern astronomical observatories on Earth today, which of the following typically happens to the image formed by the telescope? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback it is recorded using an electronic detector called a CCD for later analysis it is recorded using an electronic detector called a CCD for later analysis Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:30 PM it is recorded using an electronic detector called a CCD for later analysis

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 15/21 Problem 25: Which of the following is NOT an advantage that the Hubble Space Telescope has over large telescopes on Earth? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback the Hubble has a larger aperture than any visible- light telescope on Earth the Hubble has a larger aperture than any visible-light telescope on Earth Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:31 PM the Hubble has a larger aperture than any visible-light telescope on Earth Problem 26: The resolution of a telescope is inversely proportional to its diameter. How many times better is the resolution of the ALMA when operating at its longest baseline (which is roughly 15 km) than the resolution of the Arecibo telescope which has a 305 meter wide dish? Grade = 75% Correct Answer Student Final Submission Feedback ALMA resolution = times better ALMA resolution = times better Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 25 % Student Grade = 100 - 0 - 25 = 75% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:33 PM ALMA resolution = times better 2 Feb 01, 2024 5:33 PM ALMA resolution = times better 49.18 49.18 52.45 49.18

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 16/21 Problem 27: An amateur astronomer who has made a lot of money investing in video-game companies decides to upgrade his home telescope from an aperture of 25 cm (0.25 m) to 0.75 m. How many times more light will his new telescope collect than his old one? Grade = 100% Correct Answer Student Final Submission Feedback Light collected = times Light collected = times Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:35 PM Light collected = times Problem 28: In broad daylight, the diameter of your pupil is typically 3 mm. In dark situations, it expands to about 7 mm. How many times more light can your eye gather after it expands its aperture? Grade = 100% Correct Answer Student Final Submission Feedback Increase in light gathered = times Increase in light gathered = times Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:35 PM Increase in light gathered = times 9.000 9.000 9.000 5.444 5.440 5.440

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 17/21 Problem 29: In the dark, your pupil (the aperture of your eye) expands to a diameter of 7 mm. How many times more light can be gathered by a telescope with a 5.5 m diameter than by a fully dark-adapted eye? Grade = 100% Correct Answer Student Final Submission Feedback Increase in light gathered = times Increase in light gathered = 618367 Increase in light gathered = times Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:38 PM Increase in light gathered = 618367 Increase in light gathered = times Problem 30: The James Webb Space Telescope has a mirror with a diameter of 6 m. The Hubble Space Telescope, meanwhile, has a mirror with a diameter of 2.4 m How many times more light can the James Webb Space Telescope gather than the Hubble Space Telescope? Grade = 100% Correct Answer Student Final Submission Feedback Light gathered = times more Light gathered = times more Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:38 PM Light gathered = times more 6.173 × 10 5 6.184 × 10 5 6.184 × 10 5 6.250 6.250 6.250

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 18/21 Problem 31: Labeling Place the labels in the correct locations for a refracting telescope. Please use the drag-and-drop environment to label the missing parts of the figure. ( Please Note: Not all labels will be used.) Grade = 75% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 25 % Student Grade = 100 - 0 - 25 = 75% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:40 PM 2 Feb 01, 2024 5:41 PM Eyepiece Aperture Objective Lens Primary Mirror Secondary Mirror Eyepiece Aperture Objective Lens Primary Mirror Secondary Mirror Primary Mirror Aperture Secondary Mirror Eyepiece Objective Lens Eyepiece Aperture Objective Lens

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 19/21 Problem 32: Labeling Place the labels in the correct locations for a Newtonian reflecting telescope. Please use the drag-and-drop environment to label the missing parts of the figure. ( Please Note: Not all labels will be used.) Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:42 PM Primary Mirror Secondary Mirror Eyepiece Primary Mirror Aperture Secondary Mirror Objective Lens Eyepiece Primary Mirror Aperture Secondary Mirror Objective Lens Eyepiece Primary Mirror Aperture Secondary Mirror Objective Lens

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 20/21 Problem 33: Sorting Modern large ground-based telescopes have certain advantages over space-based telescopes, while space-based telescopes have their own advantages. Distinguish between the key advantages of a modern world-class ground-based observatory like the Keck observatory and the advantages of a telescope in space like the Hubble Space Telescope. Please use the diagram below to place choices in their corresponding buckets. Grade = 0% Correct Answer Student Final Submission Feedback Grade Summary Deduction for Final Submission 83.33 % Deductions for Incorrect Submissions, Hints and Feedback [?] 75 % Student Grade = 100 - 83.33 - 75 = 0% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 01, 2024 5:45 PM 2 Feb 01, 2024 5:46 PM Easier to access for upgrades and service Greater light-gathering power 24-hour observing cycle Better resolution No light pollution Better resolution Easier to access for upgrades and service 24-hour observing cycle No light pollution Greater light-gathering power No light pollution Greater light-gathering power Better resolution Easier to access for upgrades and service 24-hour observing cycle Greater light-gathering power No light pollution Easier to access for upgrades and service Better resolution 24-hour observing cycle

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51279 21/21 3 Feb 01, 2024 5:47 PM 4 Feb 01, 2024 5:48 PM All content © 2024 Expert TA, LLC Greater light-gathering power Better resolution Easier to access for upgrades and service 24-hour observing cycle No light pollution Better resolution Easier to access for upgrades and service 24-hour observing cycle No light pollution Greater light-gathering power

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 1/19 ASTR 1220 (Spring 2024) Pryal Homework 4: Telescopes, Science, and the Sun Kim, Mingyeong - yye5qg@virginia.edu Problem 1: You are an astronomer who wants to study a faint star in the process of being born, which gives off most of its faint radiation in the infrared. Which of the following would NOT be a step you would want to take? Please select the best choice from the available options. Grade = 75% Correct Answer Student Final Submission Feedback heat your telescope, so its delicate optics are not cold heat your telescope, so its delicate optics are not cold Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 25 % Student Grade = 100 - 0 - 25 = 75% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:43 PM shield your telescope from the radiation given off by your graduate students 2 Feb 14, 2024 7:46 PM heat your telescope, so its delicate optics are not cold Problem 2: The two regions of the electromagnetic spectrum where the Earth's atmosphere is transparent (radiation can get in) are visible light and: Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback some radio waves some radio waves Correct! Grade Summary Deduction for Final Submission 0 %

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 2/19 Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:47 PM some radio waves Problem 3: What type of telescope can be used routinely on the surface of the Earth during the DAY? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback a radio telescope a radio telescope Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:49 PM a radio telescope Problem 4: Which of the following types of telescopes can be used ONLY above the Earth's atmosphere? Please select the best choice from the available options. Grade = 100%

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 3/19 Correct Answer Student Final Submission Feedback x-ray telescope x-ray telescope Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:50 PM x-ray telescope Problem 5: In the summer of 1996, the European Space Agency announced that it would be suspending the operations of the International Ultraviolet Explorer. Astronomers who were most unhappy about that announcements were likely to be studying what types of objects? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback very hot stars very hot stars Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:51 PM very hot stars Problem 6: Why do astronomers prefer to put infrared telescopes on high-flying airplanes or on satellites in space?

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 4/19 Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback because the water vapor in the lower atmosphere is very good at absorbing infrared because the water vapor in the lower atmosphere is very good at absorbing infrared Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:51 PM because the water vapor in the lower atmosphere is very good at absorbing infrared Problem 7: What is the distinguishing characteristic of the James Webb Space Telescope (what about it really helps astronomers)? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback it has the largest mirror ever put into space for observing faint objects it has the largest mirror ever put into space for observing faint objects Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:52 PM it has the largest mirror ever put into space for observing faint objects

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 5/19 Problem 8: If you were an astronomer using the mountaintop observatory, you would have the option of detecting... Select all that apply. Grade = 100% Correct Answer Student Final Submission Feedback Radio waves , Short-wavelength infrared light , Yellow light Radio waves , Short-wavelength infrared light , Yellow light Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:54 PM Radio waves , Short-wavelength infrared light , Yellow light Problem 9: It is a normal experience on Earth to see the stars twinkle. Suppose you traveled to the Moon. Would you see stars twinkle while standing on the surface of the Moon?

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 6/19 Choose the correct answer with the best explanation. Grade = 100% Correct Answer Student Final Submission Feedback No; twinkling occurs due to atmospheric turbulence, and the Moon does not have an atmosphere. No; twinkling occurs due to atmospheric turbulence, and the Moon does not have an atmosphere. Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:55 PM No; twinkling occurs due to atmospheric turbulence, and the Moon does not have an atmosphere. Problem 10: Labeling Place the labels for each type of telescope at the best location where it would perform optimally while minimizing costs. Please use the drag-and-drop environment to label the missing parts of the figure. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Gamma ray telescope Ultraviolet telescope Infrared telescope X-ray telescope Radio telescope Optical telescope Gamma ray telescope Infrared telescope X-ray telescope Ultraviolet telescope Radio telescope Optical telescope

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 7/19 Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:56 PM Problem 11: Sorting A group of astronomers who study things across the electromagnetic spectrum have submitted proposals for various new instruments and science goals. What luck – all of the science goals are valid, and funding exists for all of them! Sort the proposals based on whether they would be better implemented as ground-based telescopes or space-based telescopes. Please use the diagram below to place choices in their corresponding buckets. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Gamma ray telescope Infrared telescope X-ray telescope Ultraviolet telescope Radio telescope Optical telescope Radio telescope that will be used to study cold hydrogen gas dispersed between galaxies. Near (short-wavelength) infrared telescope that will be used to study nearby substellar objects. Visible-wavelength telescope that will be used to search for potentially threatening asteroids down to half a kilometer in size. Near (long-wavelength) ultraviolet telescope that will be used to study young star-forming regions in other galaxies. X-ray telescope that will be used to perform a survey for active black holes. Far (short-wavelength) ultraviolet telescope that will be used to study activity in the transition region between the Sun’s chromosphere and corona. Gamma ray telescope that will be used to detect supernovae in distant galaxies. Radio telescope that will be used to study cold hydrogen gas dispersed between galaxies. Near (long-wavelength) ultraviolet telescope that will be used to study young star-forming regions in other galaxies. Visible-wavelength telescope that will be used to search for potentially threatening asteroids down to half a kilometer in size. Near (short-wavelength) infrared telescope that will be used to study nearby substellar objects. Far (short-wavelength) ultraviolet telescope that will be used to study activity in the transition region between the Sun’s chromosphere and corona. X-ray telescope that will be used to perform a survey for active black holes. Gamma ray telescope that will be used to detect supernovae in distant galaxies.

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 8/19 Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:58 PM Problem 12: Suppose a person said to you “Einstein’s theory of relativity is just a theory, so it could be wrong.” Which of the following statements would be the best response to that remark? Grade = 100% Correct Answer Student Final Submission Feedback “While it could be wrong, scientists call it a ‘theory’ because it has held up under rigorous testing so it seems pretty unlikely to be completely wrong.” “While it could be wrong, scientists call it a ‘theory’ because it has held up under rigorous testing so it seems pretty unlikely to be completely wrong.” Correct! Grade Summary Deduction for Final Submission 0 % Radio telescope that will be used to study cold hydrogen gas dispersed between galaxies. Near (long-wavelength) ultraviolet telescope that will be used to study young star-forming regions in other galaxies. Visible-wavelength telescope that will be used to search for potentially threatening asteroids down to half a kilometer in size. Near (short-wavelength) infrared telescope that will be used to study nearby substellar objects. Far (short-wavelength) ultraviolet telescope that will be used to study activity in the transition region between the Sun’s chromosphere and corona. X-ray telescope that will be used to perform a survey for active black holes. Gamma ray telescope that will be used to detect supernovae in distant galaxies.

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 9/19 Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:58 PM “While it could be wrong, scientists call it a ‘theory’ because it has held up under rigorous testing so it seems pretty unlikely to be completely wrong.” Problem 13: Suppose a person said to you “Einstein’s theory of relativity is a theory, so it must be correct.” Which of the following statements would be the best response to that remark? Grade = 100% Correct Answer Student Final Submission Feedback “While it could be correct, it is always possible that the next test could identify a flaw or weakness.” “While it could be correct, it is always possible that the next test could identify a flaw or weakness.” Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:59 PM “While it could be correct, it is always possible that the next test could identify a flaw or weakness.” Problem 14:

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 10/19 Scientific models are always an approximation of nature. Grade = 100% Correct Answer Student Final Submission Feedback TRUE TRUE Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:59 PM TRUE Problem 15: Scientific models and hypotheses can change as new experiments or observations are done, often with better equipment. Grade = 100% Correct Answer Student Final Submission Feedback TRUE TRUE Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:59 PM TRUE Problem 16: When did scientists begin to understand how the Sun produces all the energy that it does?

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 11/19 Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback The process was not well understood until the 1930's The process was not well understood until the 1930's Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 7:59 PM The process was not well understood until the 1930's Problem 17: Physicists Kelvin and Helmholtz in the last century proposed that the source of the Sun's energy could be: Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback a slow contraction a slow contraction Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:00 PM a slow contraction Problem 18: Today we realize that the source of energy for the Sun is a process called

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 12/19 Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback nuclear fusion nuclear fusion Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:01 PM nuclear fusion Problem 19: According to the formula E=mc 2 , Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback a little bit of mass can be converted into a substantial amount of energy a little bit of mass can be converted into a substantial amount of energy Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:01 PM a little bit of mass can be converted into a substantial amount of energy

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 13/19 Problem 20: When two light elements collide to undergo nuclear fusion, Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback some of the energy in their mass is released some of the energy in their mass is released Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:02 PM some of the energy in their mass is released Problem 21: When a large nucleus breaks apart (or is broken apart) into two smaller pieces, this is called Please select the best choice from the available options. Grade = 75% Correct Answer Student Final Submission Feedback nuclear fission nuclear fission Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 25 % Student Grade = 100 - 0 - 25 = 75%

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 14/19 Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:02 PM nuclear fusion 2 Feb 14, 2024 8:02 PM nuclear fission Problem 22: At the end of the p-p chain of nuclear fusion in the Sun, hydrogen nuclei have been converted into: Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback a helium nucleus a helium nucleus Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:02 PM a helium nucleus Problem 23: The Sun is an enormous ball of gas. Left to itself, a ball of so many atoms should collapse under its own tremendous gravity. Why is our Sun not collapsing? Please select the best choice from the available options. Grade = 100%

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 15/19 Correct Answer Student Final Submission Feedback nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:03 PM nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced Problem 24: The proton-proton chain is described in three steps - three reactions that happen in order to produce one 4 He nucleus. Some textbooks present this using three “nuclear formulas”, but generally the entire process is summarized with just one. What is the correct formula that succinctly summarizes the overall process of hydrogen-to-helium fusion? Grade = 100% Correct Answer Student Final Submission Feedback 4 1 H 4 He + energy 4 1 H 4 He + energy Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:04 PM 4 1 H 4 He + energy Problem 25: Suppose a star’s hydrostatic equilibrium is disrupted by a sudden slight increase in the energy generation rate in its core. → → →

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 16/19 Part (a) What will happen to the core in response? Grade = 100% Correct Answer Student Final Submission Feedback It will expand as it heats up. It will expand as it heats up. Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:04 PM It will expand as it heats up. Part (b) What happens next as a result of this change? Grade = 100% Correct Answer Student Final Submission Feedback The core cools down as it expands. The core cools down as it expands. Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:04 PM The core cools down as it expands. Part (c) How does the energy generation rate respond after that? Grade = 100% Correct Answer Student Final Submission Feedback The energy generation rate decreases slightly. The energy generation rate decreases slightly. Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:05 PM The energy generation rate decreases slightly. Part (d) What happens to the core in response to this new change?

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 17/19 Grade = 75% Correct Answer Student Final Submission Feedback Hydrostatic equilibrium is restored, returning to its original level and volume. Hydrostatic equilibrium is restored, returning to its original level and volume. Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 25 % Student Grade = 100 - 0 - 25 = 75% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:06 PM The core, and star, remain larger, establishing a new equilibrium. 2 Feb 14, 2024 8:06 PM Hydrostatic equilibrium is restored, returning to its original level and volume. Problem 26: Suppose the strength of the electromagnetic force was greater than it currently is relative to that of the strong nuclear force. How would this affect the minimum core temperature required to sustain nuclear fusion in the center of stars? Grade = 100% Correct Answer Student Final Submission Feedback The required core temperature would be higher. The required core temperature would be higher. Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:07 PM The required core temperature would be higher. Problem 27: The Sun converts 4 × 10 9 kg of mass to energy every second.

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 18/19 How many years would it take for the Sun to convert 6 × 10 24 kg (the mass of the Earth) into energy? Grade = 100% Correct Answer Student Final Submission Feedback Time = years Time = 47532132 Time = years Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:08 PM Time = 47532132 Time = years Problem 28: In the ongoing fusion reaction in the Sun, one reaction consists of four protons changing into one helium nucleus with approximately 0.02862 times the mass of a single proton converted into energy. Given that a proton has a mass of 1.67 × 10 -27 kg, how much energy in joules is produced by a single fusion reaction? Grade = 100% Correct Answer Student Final Submission Feedback E = J E = 4.3 * 10 -12 E = J Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 14, 2024 8:09 PM E = 4.3 * 10 -12 E = J 4.753 × 10 7 4.753 × 10 7 4.753 × 10 7 4.302 × 10 −12 4.300 × 10 −12 4.300 × 10 −12

3/1/24, 6:39 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51355 19/19 All content © 2024 Expert TA, LLC

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 1/22 ASTR 1220 (Spring 2024) Pryal Homework 5: The Sun & Other Stars Kim, Mingyeong - yye5qg@virginia.edu Problem 1: How do astronomers know what the outer layers of the Sun are made of? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback we take an absorption line spectrum of the Sun, and the absorption lines tell us what elements are present in the outer layers we take an absorption line spectrum of the Sun, and the absorption lines tell us what elements are present in the outer layers Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:40 PM we take an absorption line spectrum of the Sun, and the absorption lines tell us what elements are present in the outer layers Problem 2: Labeling Put the following labels where they belong on the diagram of the Sun: Please use the drag-and-drop environment to label the parts of the Sun with the correct names. Grade = 100% Correct Answer Student Final Submission Feedback Correct! corona convection zone corona convection zone

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 2/22 Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:41 PM Problem 3: Ranking The following are regions of the Sun. Please put them in order of temperature, from coolest to hottest: Grade = 75% Correct Answer Student Final Submission Feedback chromosphere core photosphere prominence radiative zone sunspot chromosphere core photosphere prominence radiative zone sunspot chromosphere core corona photosphere prominence radiative zone sunspot convection zone

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 3/22 Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 25 % Student Grade = 100 - 0 - 25 = 75% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:42 PM 2 Feb 20, 2024 7:43 PM one sunspot photosphere corona the boundary between the radiative zone and the convective zone core one sunspot photosphere corona the boundary between the radiative zone and the convective zone core one sunspot photosphere the boundary between the radiative zone and the convective zone corona core one sunspot photosphere corona the boundary between the radiative zone and the convective zone core

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 4/22 Problem 4: Ranking Arrange the layers of the Sun in order of density, from highest to lowest. Please use the drag-and-drop environment to label the missing parts of the figure from highest to lowest. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:44 PM Problem 5: Solar wind particles can be captured by the Earth's magnetosphere. When these particles spiral down along the magnetic field into the atmosphere, they are responsible for:

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 5/22 Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback aurorae (northern and southern lights) aurorae (northern and southern lights) Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:45 PM aurorae (northern and southern lights) Problem 6: The light we observe from the Sun with our eyes comes primarily from which of the labeled regions? Grade = 100% Correct Answer Student Final Submission Feedback Region E Region E Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:45 PM Region E

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 6/22 Problem 7: When energy is produced and released by the Sun’s core, it leaves the core in the form of Grade = 100% Correct Answer Student Final Submission Feedback photons photons Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:45 PM photons Problem 8: Which characteristic or feature of the Sun is not associated with the Sun’s magnetic activity? Grade = 100% Correct Answer Student Final Submission Feedback Absorption lines Absorption lines Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100%

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 7/22 Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:46 PM Absorption lines Problem 9: Labeling On the following diagram, label which spectrum belongs to a star moving away from us and which belongs to a star coming toward us. Please use the drag-and-drop environment to label the spectrum that shows motion away and the one that shows motion toward us. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:50 PM Moving away from us Moving towards us Moving away from us Moving towards us Moving away from us

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 8/22 Problem 10: Ranking Assume the five stars shown all have the same radius. If they are all located at the same distance from Earth, arrange the star images in order of their apparent brightness, dimmest to brightest. Please use the drag-and-drop environment to label the missing parts of the figure from dimmest to brightest. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:51 PM Moving towards us

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 9/22 Problem 11: Identify The image here shows a popular constellation visible in the winter sky. Click on the star that has the coolest surface temperature based on its appearance. Grade = 75% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 25 % Student Grade = 100 - 0 - 25 = 75% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:52 PM

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 10/22 2 Feb 20, 2024 7:59 PM Problem 12: Two stars have the same luminosity, but star B is three times farther away from us than star A. Compared to star A, star B will look

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 11/22 Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback nine times fainter nine times fainter Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:54 PM nine times fainter Problem 13: Two stars have the exact same luminosity, but star Y is four times dimmer looking that star X. This means that Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback star Y is twice as far away as star X star Y is twice as far away as star X Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:56 PM star Y is twice as far away as star X Problem 14: Using a good pair of binoculars, you observe a section of the sky where there are stars of many different apparent brightnesses. You find one star that appears especially dim. This star looks dim because it is:

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 12/22 Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback it could be more than one of these; there is no way to tell which answer is right by just looking at the star it could be more than one of these; there is no way to tell which answer is right by just looking at the star Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:56 PM it could be more than one of these; there is no way to tell which answer is right by just looking at the star Problem 15: Star A and Star B are located at different distances but have identical apparent brightnesses. If Star A is located times farther away than Star B, how many times more luminous is Star A than Star B? Grade = 100% Correct Answer Student Final Submission Feedback Factor = Factor = 32 2 Factor = Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:57 PM Factor = 32 2 Factor = 32 1024 1024 1024

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 13/22 Problem 16: Star A and Star B have different apparent brightnesses but identical luminosities. If Star A appears times dimmer than Star B in the sky, how many times farther away is Star A than Star B? Grade = 100% Correct Answer Student Final Submission Feedback Factor = Factor = √( 5900 ) Factor = Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 7:58 PM Factor = √( 5900 ) Factor = Problem 17: Why are astronomers much more interested in the luminosity of a star than its apparent brightness? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback because the luminosity tells us how bright a star really is, while apparent brightness only tells us how bright it happens to look from Earth because the luminosity tells us how bright a star really is, while apparent brightness only tells us how bright it happens to look from Earth Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % 5900 76.81 76.81 76.81

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 14/22 Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 8:01 PM because the luminosity tells us how bright a star really is, while apparent brightness only tells us how bright it happens to look from Earth Problem 18: What is the baseline that astronomers use to measure the parallax of the nearest stars? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback the diameter of the Earth's orbit around the Sun the diameter of the Earth's orbit around the Sun Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 8:02 PM the diameter of the Earth's orbit around the Sun Problem 19: The apparent brightness of stars in general tells us nothing about their distances; we cannot assume that the dimmer stars are farther away. In order for the apparent brightness of a star to be a good indicator of its distance, all the stars would have to be: Please select the best choice from the available options.

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 15/22 Grade = 100% Correct Answer Student Final Submission Feedback the same luminosity the same luminosity Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 8:02 PM the same luminosity Problem 20: Which of the following will show the smallest parallax shift? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback the star 51 Pegasi, about 50 light-years away the star 51 Pegasi, about 50 light-years away Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 8:02 PM the star 51 Pegasi, about 50 light-years away Problem 21: Which of the following characteristics of a single star (one that moves through space alone) is difficult to measure directly?

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 16/22 Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback its mass its mass Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 8:02 PM its mass Problem 22: Labeling On the H-R diagram below, please put the terms below in the correct place on the diagram. Please use the drag-and-drop environment to label the parts of the figure. ( Please Note: Not all labels will be used.) Grade = 100% Correct Answer Student Final Submission Feedback Correct! Grade Summary Deduction for Final Submission 0 % Surface Temperature Spectral Class Luminosity White dwarfs Red dwarfs Main Sequence Red giants Supergiants Black Holes Surface Temperature Spectral Class Luminosity White dwarfs Red dwarfs Main Sequence Red giants Supergiants Black Holes

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 17/22 Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 8:02 PM Problem 23: Labeling On the H-R diagram shown, drag each star to the position along the main sequence that most closely matches how it would appear. Please use the drag-and-drop environment to label the missing parts of the figure. Grade = 100% Correct Answer Student Final Submission Feedback Correct! Surface Temperature Spectral Class Luminosity White dwarfs Red dwarfs Main Sequence Red giants Supergiants Black Holes

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 18/22 Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 8:03 PM Problem 24: Labeling On the H-R diagram shown, drag each label to its correct position. Note: not all labels will be used. Please use the drag-and-drop environment to label the missing parts of the figure. ( Please Note: Not all labels will be used.) Grade = 100% Correct Answer Student Final Submission Feedback Correct! Most massive main sequence star Most like our Sun Largest radius Least massive main sequence star Smallest\ radius Most massive main sequence star Most like our Sun Largest radius Least massive main sequence star Smallest\ radius

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 19/22 Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 8:03 PM Problem 25: Labeling On the H-R diagram shown, drag into the box the arrow that correctly indicates the direction of increasing radius. Please use the drag-and-drop environment to label the missing parts of the figure. ( Please Note: Not all labels will be used.) Grade = 100% Correct Answer Student Final Submission Feedback Correct! Oldest Oldest Most massive main sequence star Most like our Sun Largest radius Least massive main sequence star Smallest\ radius Oldest

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 20/22 Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 8:03 PM Problem 26: Labeling On the H-R diagram shown, drag into the box the arrow that correctly indicates the direction of decreasing core temperature along the main sequence. Please use the drag-and-drop environment to label the missing parts of the figure. ( Please Note: Not all labels will be used.) Grade = 100% Correct Answer Student Final Submission Feedback Correct!

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 21/22 Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 20, 2024 8:03 PM Problem 27: Astronomers identify the main sequence on the H-R diagram with what activity in the course of a star's life? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback fusing hydrogen into helium in their cores fusing hydrogen into helium in their cores Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work.

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51432 22/22 Date Time Answer Hints Feedback 1 Feb 20, 2024 8:03 PM fusing hydrogen into helium in their cores All content © 2024 Expert TA, LLC

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51527 1/20 ASTR 1220 (Spring 2024) Pryal Homework 6: Star Clusters and the Birth of Star Sy Kim, Mingyeong - yye5qg@virginia.edu Problem 1: In a science fiction television show set in the far future, a starship finds itself approaching a stellar association. What types of objects would they be most likely to notice in such an association as they approach? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback bright O and B type stars bright O and B type stars Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 28, 2024 7:31 PM bright O and B type stars Problem 2: As a cluster of stars begins to age, which type of star in the cluster will move off the main sequence of the H-R diagram first? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback the O and B type stars the O and B type stars Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100%

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51527 2/20 Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 28, 2024 7:32 PM the O and B type stars Problem 3: On an H-R diagram of a cluster of stars, which characteristic of the diagram do astronomers use as a good indicator of the cluster's age? Please select the best choice from the available options. Grade = 100% Correct Answer Student Final Submission Feedback the point on the main sequence where stars begin to "turn off" -- to move toward the red giant region the point on the main sequence where stars begin to "turn off" -- to move toward the red giant region Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 28, 2024 7:33 PM the point on the main sequence where stars begin to "turn off" -- to move toward the red giant region

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51527 3/20 Problem 4: The figure shows an H-R diagram of stars from two clusters: M67 and NGC 188. Based on what is shown here, which cluster is older? Grade = 100% Correct Answer Student Final Submission Feedback NGC 188 NGC 188 Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 28, 2024 7:35 PM NGC 188

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51527 4/20 Problem 5: The H-R diagram below shows the positions of stars from a Milky Way star cluster, with the Sun’s present position also shown for reference. Based on this, how does this cluster’s age compare to that of the Sun? Grade = 100% Correct Answer Student Final Submission Feedback Younger Younger Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 % Student Grade = 100 - 0 - 0 = 100% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 28, 2024 7:38 PM Younger Problem 6: The H-R diagram below shows the positions of stars from a Milky Way star cluster, with the Sun’s present position also shown for reference.

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51527 5/20 Based on this, how does this cluster’s age compare to that of the Sun? Grade = 0% Correct Answer Student Final Submission Feedback Younger Older The main sequence stars have only just begun evolving off (look at the top-left corner), so the cluster cannot be older than the Sun (which is, itself, still on the main sequence). Grade Summary Deduction for Final Submission 100 % Deductions for Incorrect Submissions, Hints and Feedback [?] 66 % Student Grade = 100 - 100 - 66 = 0% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 28, 2024 7:38 PM Same age 2 Feb 28, 2024 7:38 PM It is not possible to determine from this figure 3 Feb 28, 2024 7:38 PM Older Note: Feedback not accessed. Problem 7: The H-R diagram on the top right shows the positions of stars from a Milky Way star cluster, with the Sun’s present position also shown for reference.

3/1/24, 6:40 AM The Expert TA | Human-like Grading, Automated! https://usa48va.theexpertta.com/Common/GradeSheetGradeReport.aspx?z=1&eid=4634&aid=51527 6/20 Based on the main sequence lifetimes shown below the diagram (Table 22.1 OpenStax), which value is the best estimate for the age of this cluster? Grade = 36% Correct Answer Student Final Submission Feedback 10 million years 10 million years Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 64 % Student Grade = 100 - 0 - 64 = 36% Submission History All Date times are displayed in Eastern Standard Time. Red submission date times indicate late work. Date Time Answer Hints Feedback 1 Feb 28, 2024 7:41 PM 500 million years -The age can be determined by determining the mass of the stars that are just evolving off the main sequence. The mass affects many properties of the star, including its surface temperature. 2 Feb 28, 2024 7:44 PM 3 billion years 3 Feb 28, 2024 7:44 PM 5 billion years 4 Feb 28, 2024 8:08 PM 10 million years Problem 8: The H-R diagram below shows the positions of stars from a Milky Way star cluster, with the Sun’s present position also shown for reference. Based on this, how does this cluster’s age compare to that of the Sun? Grade = 100% Correct Answer Student Final Submission Feedback Older Older Correct! Grade Summary Deduction for Final Submission 0 % Deductions for Incorrect Submissions, Hints and Feedback [?] 0 %