123Aex3verBsol - Name_Student ID Score last first I A thin layer of oil(n = 1.45 floats on a thick slab of glass(n = 1.60 as shown The oil varies

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Name ___________________________________ Student ID ____________ Score_______ last first Physics 123A, Spring 09, Version B Exam 3, page 1 I. A thin layer of oil (n = 1 . 45) floats on a thick slab of glass (n = 1 . 60) as shown. The oil varies in thickness from 0 to 400 nm. Sunlight from directly overhead strikes the oil layer, and an observer looking straight down toward the glass sees only certain color(s) of reflected light. 1. (4 pts) Which choice best describes the color(s) of light that will be strongly reflected at the tip of the oil wedge (zero thickness)? A. Red colors ( λ 650 nm in air). B. Green colors ( λ 550 nm in air). C. Blue colors ( λ 450 nm in air). D. All colors will be strongly reflected (white reflection). E. No colors will be strongly reflected (darkness). 2. (5 pts) Suppose that only green light ( λ = 550 nm in air) shines onto the oil wedge. Which choice best represents the number of different thicknesses (include zero at the tip) where this green light is brightly reflected, considering the entire length of the oil wedge? A. Zero – no strong green reflection anywhere along the wedge. B. One – there is one thickness that produces strong green reflection. C. Two – there are two thicknesses that produce strong green reflection. D. Three – there are 3 thicknesses that produce strong green reflection. E. More than 3 – there are many thicknesses that strongly reflect green light. 3. (5 pts) Which choice best represents a wavelength of visible light that would experience complete destructive interference where the oil thickness is 250 nm? More than one 725 nm 483 nm 460 nm 445 nm such wavelength A B C D E Useful Data: h = 6 . 63 × 10 -34 J s 1 . 000 eV = 1 . 602 × 10 -19 J Oil Glass Air This end 400 nm thick
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Name ___________________________________ Student ID ____________ Score_______ last first Physics 123A, Spring 09, Version B Exam 3, page 2 II. Photons When electromagnetic radiation of wavelength λ = 318 nm strikes a metal plate, the maximum kinetic energy of ejected electrons is found to be 1 . 80 eV. 4.
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This note was uploaded on 06/07/2009 for the course PHYS 123 taught by Professor Boynton during the Spring '09 term at University of Washington.

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123Aex3verBsol - Name_Student ID Score last first I A thin layer of oil(n = 1.45 floats on a thick slab of glass(n = 1.60 as shown The oil varies

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