Old Examination 1 with Answers - University Physics III | PHYS 262, Study notes of Physics

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Physics 262 - exam#1 1. (25pts) Answer the following questions. Justify your answers, (Use the space provided below and the next page) a). Which of the following objects (arrows) will produce real images? Which images will be inverted? p Al) . i) >) ii) a). f f f f f b). A spy plane sends a sonar signal toward the surface of the ocean. If the speed of propagation for sound waves is faster in water than in air, will the sonar signal tends to bend toward or away from the normal direction as it refracts from the air into the ocean? c). On the ground of a gas station, one observes a bright spot at the thinnest region of an oil film on water. Near another comer, there is an unknown substance on top of a layer of water. At the thinnest part of this substance, one observes a dark spot. Is the index of refiaction for this unknown substance larger or smaller then the index of tefraction of oil? d). A small aperture with a size of few millimeters is used in a difffaction experiment and you have a choice on the wavelength of the light source: xrays (A ~107'°m), visible lights (A ~1077m), infrared lights (A ~10~n1), and radio waves (A ~ 1m), which one is most likely to produce measurable diffraction fringes? a) ivirtual and upright; ii) real and inverted; iii) virtual and upright b) By Snell’s law, the refracted angle should be larger than the incident angle. In one Wg be sonar Signal wil bend away from the nor c) Nf air aw MM a $ ste f weler canect bright spvtet Ha thered dark spot ah (irae hese cht, implies thet cays +2 Jot > ont O offers &P bath caller itu® tee pwee ant iE > har ong and We? N welem go thal ake are afl! pave Roel : $y Wehay@ ne > mat | => Naw é Net < Ayer pS d) For the fringes to be observable, we should have >) £0 and the inffared light will best satisfy this criterion. 3/8