Class: Date: Exam 4--PHYS 102--S16 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Consider this 2-lens system. What is the final magnification? a. 1 4 d. + 1 2 b. +3 e. +2 c. 0 2. Mirrors experience which of these aberrations: I. Spherical Aberration II. Chromatic Aberration a. I b. II c. I & II d. neither of these 3. You look at something far away. Then, you look at something closer. How has the focal length of your eye lens changed? a. f has increased b. f has decreased c. f remained the same d. none of these 4. Which of the following effects is the result of the fact that the index of refraction of glass will vary with wavelength? a. spherical aberration b. chromatic aberration c. light scattering d. mirages 5. An object is placed at a distance of 50 cm from a lens along the axis. If a real image forms at a distance of 40 cm from the lens, on the opposite side from the object, what is the focal length of the lens? a. 90 cm b. 200 cm c. 22 cm d. 45 cm 6. Which of the following best describes the image for a convex lens that forms whenever the object is at a distance less than one focal length from the lens? a. inverted, diminished and real b. inverted, enlarged and real c. upright, diminished and virtual d. upright, enlarged and virtual 1
7. An object is 6.0 cm from a convex lens along its axis. The lens has a focal length of 9.0 cm. What are the respective values of the image distance and magnification? 10. A diffraction grating has 12000 lines/cm. Light of wavelength 436 nm is incident on the grating. How many bright spots are on the screen? a. q= 18 cm and M=3.0 b. q=3.0 cm and M= 0.50 c. q=18 cm and M=3.0 d. q= 18 cm and M= 3.0 8. Which of these rays is drawn incorrectly? a. 1 b. 2 c. 3 d. 5 11. This figure shows a double-slit diffraction pattern. What is the path-length difference of the light rays that interfere to produce the designated bright fringe (with the arrow)? a. (a) b. (b) c. (c) d. (a) & (c) e. (a) & (b) 9. A diffraction grating has 2000 lines/mm. What is the slit separation? a. 4.0x10-7 m b. 2.0x10-7 c. 2.5x10-7 m d. 5.0x10-7 m a. 2 wavelengths b. 2.5 wavelengths c. 3 wavelengths d. 3.5 wavelengths 12. In a Young's double-slit interference apparatus, by what factor is the distance between adjacent light and dark fringes changed when the separation between the slits is doubled? a. 1 b. 2 c. 1/2 d. 1/4 2
13. A light of wavelength 550 nm illuminates a double slit. The separation between the slits is 5.2x10-6 m. What is the angle to the 2nd order bright fringe? 16. Light of wavelength 610 nm is incident on a slit of width 0.20 mm and a diffraction pattern is produced on a screen that is 1.5 m from the slit. What is the distance of the second dark fringe from the center of the bright fringe? (1 nm = 10 9 m) a. 0.02 degrees b. 12 degrees c. 8.3 degrees d. 3.2 degrees 14. By what amount are these two waves out of phase? a. 0.68 cm b. 1.2 cm c. 1.4 cm d. 0.92 cm 17. The pitch of an individual s voice is modulated by changing. a. the mass of the vocal cords b. the size of the glottis c. the tension of the vocal cords d. the length of the vocal cords a. 0º b. 45º c. 90º d. 180º e. 360º 15. Two electromagnetic waves have a wavelength of 3.0 m. They are coherent and initially in-phase. One travels 4.0 meters to a screen. Another travels 2.5 meters to the same point on the screen. On the screen, you observe... a. somewhere between a dark and bright spot b. it depends on the frequency c. a bright spot d. a dark spot 18. Consider this figure. What best describes the part labeled (1)? a. larynx b. trachea c. glottis d. vocal cords e. thyroid 3
19. Consider this diagram for the next set of questions: 22. A sound has an intensity level of 24 db. What is the intensity of this sound? Which of these is called the cochlea? a. (2) b. (4) c. (5) d. (6) e. (7) 20. 50 db is times as intense as 30 db. a. 20 b. 1.7 c. 0.6 d. 1500 e. 100 21. You stand 1 meter from a speaker and measure the intensity to be 0.1 W/m 2. How far away should you stand so that the intensity is 0.001 W/m 2? a. 3 m b. 10 m c. 5 m d. 100 m a. 2.5x10-10 W/m 2 b. 0.38 W/m 2 c. 9.1 W/m 2 d. 0.0034 W/m 2 e. 24 W/m 2 23. Two loudspeakers are in phase and produce a single tone with a wavelength of 2.0 m. A microphone is located 8 meters from one of the speakers and 12 meters from the other speaker. What will the microphone detect? a. no sound at all b. a loud sound c. a quiet sound 24. Two tones are played on a guitar. One tone is 140 Hz. The other is 143 Hz. What is the frequency of the beats? a. 0 Hz b. 1.02 Hz c. 3 Hz d. 140 Hz 25. The tension in a guitar string is increased by a factor of 2. By what factor does the wave velocity change? a. 1.4 b. 2.0 c. 0.7 d. 0.5 4
26. Consider this standing wave on a string, fixed at both ends, for the next set of questions: If the length of the string (l) is 3 m, what is the wavelength of the standing wave? a. 6 m b. 4 m c. 3 m d. 2 m e. 4.5 m 30. The speed of a wave depends on which of these: I. Frequency II. Wavelength III. Medium a. I & II b. I, II, & III c. III only d. II & III e. none of these 27. For the wave in the previous question, which harmonic is this? a. 2nd b. 3rd c. 4th d. 5th e. 6th 28. If the speed of a wave is 3 m/s and its wavelength is 0.10 m, what is its period? a. 0.3 s b. 0.03 s c. 0.01 s d. 0.1 s e. 30 s 29. Which of these shows the wavelength of this transverse wave? a. A b. B c. C d. D 5
Exam 4--PHYS 102--S16 Answer Section MULTIPLE CHOICE 1. ANS: D PTS: 1 REF: S16 2. ANS: A PTS: 1 REF: S16 3. ANS: B PTS: 1 REF: S16 4. ANS: B PTS: 1 REF: S16 5. ANS: C PTS: 1 REF: S16 6. ANS: D PTS: 1 REF: S16 7. ANS: A PTS: 1 REF: S16 8. ANS: C PTS: 1 REF: S16 9. ANS: D PTS: 1 REF: S16 10. ANS: C PTS: 1 REF: S16 11. ANS: B PTS: 1 REF: S16 12. ANS: C PTS: 1 REF: S16 13. ANS: B PTS: 1 REF: S16 14. ANS: C PTS: 1 REF: S16 15. ANS: D PTS: 1 REF: S16 16. ANS: D PTS: 1 REF: S16 17. ANS: C PTS: 1 REF: S16 18. ANS: A PTS: 1 REF: S16 19. ANS: D PTS: 1 REF: S16 20. ANS: E PTS: 1 REF: S16 21. ANS: B PTS: 1 REF: S16 22. ANS: A PTS: 1 REF: S16 23. ANS: B PTS: 1 REF: S16 24. ANS: C PTS: 1 REF: S16 25. ANS: A PTS: 1 26. ANS: D PTS: 1 REF: S16 27. ANS: B PTS: 1 REF: S16 28. ANS: B PTS: 1 REF: S16 29. ANS: B PTS: 1 REF: S16 30. ANS: C PTS: 1 REF: S16 1