ก e ধে T LITT + Problem 4: Two identical loudspeakers send identical sound waves out to a listener at x = 20 m. The speakers are respectively located at (0;0) m and (0;7.61) m. The frequency of the two waves is slowly increased from a very low value. Give the first four wavelengths at which minimum sound will be hear. Problem 5: A siren with a frequency of 1000 Hz moves away from you directly towards a cliff at a speed of 10.0 m/s. a) What is the frequency of the sound you hear directly from the siren? b) What is the frequency of the sound you hear reflected from the cliff? c) What beat frequency would you detect? d) If you now moved towards the cliff at 5.0 m/s along the same line as the siren, what beat frequency would you now detect? Problem 6: A thin film of alcohol (n = 1.36) lies on a flat glass plate (n = 1.51). Monochromatic light, whose wavelength can be changed, is incident normally and the intensity of the reflected light is a minimum for wavelength of 512 nm and a maximum for wavelength of 640 nm. What is the thickness of the film? As a part of your answer, you must include a diagram that clearly shows the rays that will interfere and the phase shift of all relevant rays. Problem 7: A double-slit experiment is set up using a laser with wavelength 633 nm. Then a very thin piece of glass (n=1.50) is placed over one of the slits. Afterward, the central point on the screen is occupied by what had been the m = 10 dark fringe. How thick is the glass? Problem 8: The figure shows a transparent hemisphere with radius R and index of refraction n. What is the maximum distance d for which a light ray parallel to the axis refracts out trough the curved surface? n d Page 2

ก e ধে T LITT + Problem 4: Two identical loudspeakers send identical sound waves out to a listener at x = 20 m. The speakers are respectively located at (0;0) m and (0;7.61) m. The frequency of the two waves is slowly increased from a very low value. Give the first four wavelengths at which minimum sound will be hear. Problem 5: A siren with a frequency of 1000 Hz moves away from you directly towards a cliff at a speed of 10.0 m/s. a) What is the frequency of the sound you hear directly from the siren? b) What is the frequency of the sound you hear reflected from the cliff? c) What beat frequency would you detect? d) If you now moved towards the cliff at 5.0 m/s along the same line as the siren, what beat frequency would you now detect? Problem 6: A thin film of alcohol (n = 1.36) lies on a flat glass plate (n = 1.51). Monochromatic light, whose wavelength can be changed, is incident normally and the intensity of the reflected light is a minimum for wavelength of 512 nm and a maximum for wavelength of 640 nm. What is the thickness of the film? As a part of your answer, you must include a diagram that clearly shows the rays that will interfere and the phase shift of all relevant rays. Problem 7: A double-slit experiment is set up using a laser with wavelength 633 nm. Then a very thin piece of glass (n=1.50) is placed over one of the slits. Afterward, the central point on the screen is occupied by what had been the m = 10 dark fringe. How thick is the glass? Problem 8: The figure shows a transparent hemisphere with radius R and index of refraction n. What is the maximum distance d for which a light ray parallel to the axis refracts out trough the curved surface? n d Page 2