Astronomy
1st Edition
ISBN: 9781938168284
Author: Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher: OpenStax
expand_more
expand_more
format_list_bulleted
Concept explainers
Textbook Question
Chapter 20, Problem 36E
H II regions can exist only if there is a nearby star hot enough to ionize hydrogen. Hydrogen is ionized only by
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
A 0.185 H inductor is connected in series with a 98.5 Ω resistor and an ac source. The voltage across the inductor is vL=−(12.5V)sin[(476rad/s)t]vL.
Derive an expression for the voltage vR across the resistor.
Express your answer in terms of the variables L, R, VL (amplitude of the voltage across the inductor), ω, and t. What is vR at 2.13 ms ? Please explain all steps
A worker lifts a box under the following conditions:Horizontal distance (H): 30 cmInitial height (V): 60 cmVertical travel (D): 50 cmTorso rotation (A): 30°Frequency: 3 times/minute for 1 hourGrip: Good
Question:What is the RWL for this task?What does this value mean in terms of occupational safety?
Can someone help
Chapter 20 Solutions
Astronomy
Ch. 20 - Identify several dark nebulae in photographs in...Ch. 20 - Why do nebulae near hot stars look red? Why do...Ch. 20 - Describe the characteristics of the various kinds...Ch. 20 - Prepare a table listing the different ways in...Ch. 20 - Describe how the 21-cm line of hydrogen is formed....Ch. 20 - Describe the properties of the dust grains found...Ch. 20 - Why is it difficult to determine where cosmic rays...Ch. 20 - What causes reddening of starlight? Explain how...Ch. 20 - Why do molecules, including H2 and more complex...Ch. 20 - Why can’t we use visible light telescopes to study...
Ch. 20 - The mass of the interstellar medium is determined...Ch. 20 - Where does interstellar dust come from? How does...Ch. 20 - Figure 20.2 shows a reddish glow around the star...Ch. 20 - If the red glow around Antares is indeed produced...Ch. 20 - Even though neutral hydrogen is the most abundant...Ch. 20 - The terms H II and H2 are both pronounced “H two.”...Ch. 20 - Suppose someone told you that she had discovered H...Ch. 20 - Describe the spectrum of each of the following: A....Ch. 20 - According to the text, a star must be hotter than...Ch. 20 - From the comments in the text about which kinds of...Ch. 20 - One way to calculate the size and shape of the...Ch. 20 - New stars form in regions where the density of gas...Ch. 20 - Thinking about the topics in this chapter, here is...Ch. 20 - Stars form in the Milky Way at a rate of about 1...Ch. 20 - The 21-cm line can be used not just to find out...Ch. 20 - Astronomers recently detected light emitted by a...Ch. 20 - We can detect 21-cm emission from other galaxies...Ch. 20 - We have said repeatedly that blue light undergoes...Ch. 20 - Suppose that, instead of being inside the Local...Ch. 20 - Suppose that, instead of being inside the Local...Ch. 20 - A molecular cloud is about 1000 times denser than...Ch. 20 - Would you expect to be able to detect an H II...Ch. 20 - Suppose that you gathered a ball of interstellar...Ch. 20 - At the average density of the interstellar medium,...Ch. 20 - Consider a grain of sand that contains 1 mg of...Ch. 20 - H II regions can exist only if there is a nearby...Ch. 20 - In the text, we said that the five-times ionized...Ch. 20 - Dust was originally discovered because the stars...Ch. 20 - How would the density inside a cold cloud (T=10K)...Ch. 20 - The text says that the Local Fluff, which...
Additional Science Textbook Solutions
Find more solutions based on key concepts
1. Why is the quantum-mechanical model of the atom important for understanding chemistry?
Chemistry: Structure and Properties (2nd Edition)
Draw the mechanism for the hydroxide ion-catalyzed cleavage of fructose-l.6-bisphosphate.
Organic Chemistry (8th Edition)
10.71 Identify each of the following as an acid or a base: (10.1)
H2SO4
RbOH
Ca(OH)2
HI
...
Chemistry: An Introduction to General, Organic, and Biological Chemistry (13th Edition)
Calculate the mass of NaCl in a 35-mL sample of a 1.3 M NaCl solution.
Introductory Chemistry (6th Edition)
What name is given to the zone of greatest seismic activity?
Applications and Investigations in Earth Science (9th Edition)
Which one of the following is not a fuel produced by microorganisms? a. algal oil b. ethanol c. hydrogen d. met...
Microbiology: An Introduction
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- Can someone help mearrow_forward3. Four identical small masses are connected in a flat perfect square. Rank the relative rotational inertias (IA, IB, IC) about the three axes of rotation shown. Axes A and B are in the plane of the square, and axis C is perpendicular to the plane, through mass m1. ΙΑ IB m2 m1 m3 Ic m4 (a) IAarrow_forwardConsider the circuit shown in the figure below. (Assume L = 5.20 m and R2 = 440 Ω.) (a) When the switch is in position a, for what value of R1 will the circuit have a time constant of 15.4 µs? (b) What is the current in the inductor at the instant the switch is thrown to position b?arrow_forwardCan someone helparrow_forwardCan someone help mearrow_forwardA particle in a box between x=0 and x=6 has the wavefunction Psi(x)=A sin(2πx). How muchenergy is required for the electron to make a transition to Psi(x)= A’ sin(7π x/3). Draw anapproximate graph for the wavefunction. Find A and A'arrow_forwardA proton is moving with 10^8 m/s speed. Find the De Broglie wavelength associated with theproton and the frequency of that wave.arrow_forwardFind the wavelength of the photon if a (Li--) electron makes a transition from n=4 to n=3. Findthe Bohr radius for each state.arrow_forwardA photon with wavelength 3000 nm hits a stationary electron. After the collision electron isscattered to 60 degrees. Find the wavelength and frequency of the scattered photon.arrow_forwardA metal has threshold frequency 10^15. Calculate the maximum kinetic energy of the ejectedelectron if a laser beam with wavelength 1.5 10^-7 m is projected on the metal.arrow_forwardDetermine the direction of the vector V, B, or ♬ that is missing from the pair of vectors shown in each scenario. Here, u is the velocity vector of a moving positive charge, B is a constant and uniform magnetic field, and F is the resulting force on the moving charge. 1. 2. 3. B OB F 4. ↑F F 5. 怔 ↑ ↑F Answer Bank 6. ↑ TE Farrow_forwardTwo point charges (+9.80 nC and -9.80 nC) are located 8.00 cm apart. Let U=0 when all of the charges are separated by infinite distances. What is the potential energy if a third point charge q=-4.20 nC is placed at point b? 8.00 cm 8.00 cm 4.00 +4.00 +4.00- cm cm cm HJarrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_ios
Recommended textbooks for you
AstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStax
Foundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
Stars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage Learning
Stars and GalaxiesPhysicsISBN:9781305120785Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
Horizons: Exploring the Universe (MindTap Course ...PhysicsISBN:9781305960961Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
Astronomy
Physics
ISBN:9781938168284
Author:Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher:OpenStax
Foundations of Astronomy (MindTap Course List)
Physics
ISBN:9781337399920
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
Stars and Galaxies (MindTap Course List)
Physics
ISBN:9781337399944
Author:Michael A. Seeds
Publisher:Cengage Learning
Stars and Galaxies
Physics
ISBN:9781305120785
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
Horizons: Exploring the Universe (MindTap Course ...
Physics
ISBN:9781305960961
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning