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Unformatted text preview: Version PREVIEW – HW 6 – Savrasov – (39824) 1 This printout should have 8 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. Serway CP 24 29 001 10.0 points Heliumneon laser light of wavelength 766 . 7 nm is sent through a 0 . 231 mm wide single slit. What is the width of the central maximum on a screen 1 . 5 m from the slit? Correct answer: 9 . 95714 mm. Explanation: Given : λ = 766 . 7 nm = 7 . 667 × 10 − 7 m , L = 1 . 5 m , and a = 0 . 231 mm = 0 . 000231 m . y L θ We use the fact that for small θ . tan θ ≈ sin θ . tan θ = y L , and sin θ = λ a For small θ , tan θ = sin θ , so y L = λ a , and since the width x of the central maximum is equal to 2 y , x = 2 y = 2 λ L a = 2 (7 . 667 × 10 − 7 m) (1 . 5 m) . 000231 m · 1000 mm 1 m = 9 . 95714 mm . Second Order Bright Fringe 02 002 10.0 points The secondorder bright fringe in a single slit diffraction pattern is 1 . 44 mm from the center of the central maximum. The screen is 78 . 3 cm from a slit of width 0 . 828 mm. Assuming monochromatic incident light, calculate the wavelength. Correct answer: 609 . 104 nm. Explanation: Bright fringes will be located approx imately midway between adjacent dark fringes. Therefore for the second bright fringe we assume that m = 2 and sin θ = parenleftbigg m + 1 2 parenrightbigg λ a = y L ....
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 Fall '09
 RichardScalettar
 Light, Wavelength, 1 L, λ, Bragg, 0.783 m

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