Reading Assignment Thin Films and Newton's Rings

11/16/23, 6:31 PM Reading Assignment 10: Thin Films and Newton's Rings: Attempt review Started on Sunday, 22 November 2020, 1:38 PM State Finished Completed on Sunday, 22 November 2020, 2:00 PM Time taken 22 mins 40 secs Marks 5.00/5.00 Grade 100.00 out of 100.00 https://eclass.srv.ualberta.ca/mod/quiz/review.php?attempt=6550731&cmid=4375424 1/7

11/16/23, 6:31 PM Reading Assignment 10: Thin Films and Newton's Rings: Attempt review Question 1 Correct Mark 1.00 out of 1.00 A ray of light travels through the glass wall of an aquarium. When the light reaches the interface between glass (n = 1.5) and water (n = 1.33) with near-normal incidence, which of the following events is/are likely to occur? sse|d 191eM Caution: this question may (or may not) have more than one correct answer. To get full marks you must select all correct responses and no incorrect ones. Select all that apply: Total internal reflection All of the light is transmitted into the water because both media are transparent The light is partially reflected and partially transmitted The reflected light is completely polarized The reflected light undergoes a 180 degree phase shift The reflected light undergoes no reflection phase shift The transmitted light undergoes a 180 degree phase shift The transmitted light undergoes no phase shift Your answer is correct. Cross out Cross out Cross out Ccross out cross out Cross out ¢ Cross out Cross out The angle of incidence is zero so this cannot be above the critical angle. At any boundary light is partially reflected and transmitted and since a zero angle of incidence cannot be Brewster's angle the reflected light cannot be perfectly polarized. Finally since the glass has a higher refractive index than water the reflected ray will not undergo a phase shift. The correct answers are: The light is partially reflected and partially transmitted, The reflected light undergoes no reflection phase shift, The transmitted light undergoes no phase shift Marks for this submission: 1.00/1.00. https://eclass.srv.ualberta.ca/mod/quiz/review.php?attempt=6550731&cmid=4375424 27

11/16/23, 6:31 PM Reading Assignment 10: Thin Films and Newton's Rings: Attempt review Question 3 Correct Mark 1.00 out of 1.00 Light of wavelength of 571 nm in vacuum is normally incident upon a thin flake of a transparent mineral with refractive index 2.0. The thickness of the flake is L = 10 um. As the light traverses the mineral (in one direction), how many wavelengths can "fit" within the thickness of the flake? Enter your answer as a decimal number with three significant figures. Answer:| 35.026 V4 The wavelength inside the refractive medium is A/n. The number of wavelengths that can "fit" in the 10 micron thickness of the mineral is _ (10um)(n) N (Anm) The correct answer is: 35.0 Marks for this submission: 1.00/1.00. https://eclass.srv.ualberta.ca/mod/quiz/review.php?attempt=6550731&cmid=4375424 47

11/16/23, 6:31 PM Reading Assignment 10: Thin Films and Newton's Rings: Attempt review Question 4 Correct Mark 1.00 out of 1.00 In an experiment, white light is shone vertically down upon a convex spherical lens that is resting (curved side down) on a flat piece of glass. Which of the following statements correctly explain why there is there a dark ring at the centre of the resulting interference pattern? NOTE: More than one of the statements may be correct. To get full marks all correct and no incorrect statements must be selected. \ 'S Select all that apply: Destructive interference of two reflected rays occurs Cross out « Destructive interference of the reflected ray and the refracted ray cross out occurs Constructive interference of two reflected rays occurs cross out The thickness of the air wedge is equal to one-half wavelength at cross out that location The thickness of the air wedge is negligible at that location Cross out «# There is a 180 degree phase difference (due to reflection) Cross out « between the two reflected rays Your answer is correct. The first reflection occurs at the top of the air film, where ngj555 > Ngir, 80 the first ray undergoes no phase shift due to reflection. The second reflection occurs at the bottom of the air film where the second medium (glass) has the higher index of refraction, so the second ray does undergo a reflection phase shift of 180 degrees (or 1 radians). The result is that the two reflected rays interfere destructively because they are 180 degrees out of phase (due to reflection). The thickness of the air-wedge is negligible at the centre (where the two pieces of glass are in contact, or nearly so) so there is no signifcant path-length difference to contribute to the phase difference. Therefore the phase difference must arise due to reflection only. The correct answers are: Destructive interference of two reflected rays occurs, The thickness of the air wedge is negligible at that location, There is a 180 degree phase difference (due to reflection) between the two reflected rays Marks for this submission: 1.00/1.00. https://eclass.srv.ualberta.ca/mod/quiz/review.php?attempt=6550731&cmid=4375424 5/7

11/16/23, 6:31 PM Reading Assignment 10: Thin Films and Newton's Rings: Attempt review Question 6 Complete Not graded Which topics or concepts in this part of light waves did you have the most trouble understanding? [Answering this question is optional and does not count towards your assignment mark.] https://eclass.srv.ualberta.ca/mod/quiz/review.php?attempt=6550731&cmid=4375424 717