19) An astronomer is trying to observe two distant stars. The stars are marginally resolved when she looks at them thru a filter that passes green light with an approximate wavelength of 555 nm. Ignoring the effects of the Earth's atmosphere, which of the following actions would improve the resolution? A. replacing the filter with one having a shorter wavelength and replacing the lens with one having a smaller diameter B. replacing the filter with one having a longer wavelength and replacing the lens with one having a shorter focal length C. replacing the filter with one having a longer wavelength and replacing the lens with one having a longer focal length D. replacing the filter with one having a shorter wavelength and replacing the lens with one having a larger diameter 20) A block oscillating on a spring has a period of 8.0 s. What is the period if the block's mass is quadrupled? im 022 9 A. 1.0 s B. 2.0 s C. 4.0 s D. 8.0 s E. 16.0 s 21) For a wave pulse on a string to travel half as fast, the string tension must be A. This is not possible; the pulse speed is always the same B. Decreased to one fourth its initial value C. Decreased to one half its initial value D. Increased by a factor of 4 E. Increased by a factor of 2 nenseighd set 22) Which of the following changes will decrease the frequency of the lowest-frequency standing sound wave on a stretched string? A. Halving the length of the string B. Increasing the tension in the string C. Replacing the string with a thicker string D. Plucking the string harder 990 10 (81 23) In a double slit experiment, if the separation between the two slits is 0.050 mm and the distance from the slits to a screen is 4.0 m, find the spacing between the first-order and second- order bright fringes when coherent light of wavelength 600 nm illuminates the slits. A. 1.2 cm oslins 1975w ad) B. 2.4 cm C. 4.8 cm D. 7.2 cm E. 9.6 cm 15) A sinusoidal wave traveling on a string has an amplitude of 5.0 cm, a period of 0.15 s, and a wavelength of 2.35 m. What is the speed at which this wave is traveling? A. 15.7 m/s B. 12.1 m/s C. 8.33 m/s D. 5.65 m/s E. 3.67 m/s 16) The figure shows a standing wave on a 140 cm long string that has been fixed at both ends and is oscillating at 400 Hz. What is the wave speed? A. 280 m/s B. 560 m/s C. 210 m/s D. 140 m/s E. 1120 m/s 17) A single-slit diffraction experiment is performed underwater and a diffraction pattern is observed on the detector screen. If the entire single-slit diffraction apparatus is then removed from the water into air, what happens to the central bright fringe? A. The central bright fringe will have the same width B. The diffraction pattern will disappear C. The central bright fringe will get wider D. The central bright fringe will get narrower 18) A fish is in an aquarium with flat sides and outside the aquarium a hungry cat is looking in at the fish. To the cat, the distance to the fish appears to be is A. less than the actual distance because light rays exiting the water and entering the air bend toward the normal B. more than the actual distance because light rays exiting the water and entering the air bend toward the normal C. more than the actual distance because light rays exiting the water and entering the air bend away from the normal D. less than the actual distance because light rays exiting the water and entering the air bend away from the normal E. the same as the actual distance