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Lecture 33. Review for Exam 4 Interference, Diffraction Reflection, Refraction. An interference pattern from 2 slits is observed on a screen. If d is doubled. The interference pattern does not change The fringe spacing doubles The fringe spacing is halved Need to know wavelength.
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Lecture 33 Review for Exam 4 Interference, Diffraction Reflection, Refraction
An interference pattern from 2 slits is observed on a screen. If d is doubled • The interference pattern does not change • The fringe spacing doubles • The fringe spacing is halved • Need to know wavelength
Diffraction grating problem • In order to determine the spacing d, of a diffraction grating (often called the grating constant), I shown a HeNe laser (λ=633nm) through the grating. On a screen 50cm away, I measured the distance between the central, m=0 bright fringe and the m=1 bright fringe and found the distance to be 9.65 cm. • What is the d?
What is n for this material? • Light incident from air, λ = 540 nm • What is the critical angle for total internal reflection? 400 300
The interference pattern from 2 slits is observed. As λ is increased • The fringe spacing increases • The fringe spacing decreases • Does not change • Need to know λ • Need more information
Question • What is the difference between diffuse and specular reflection? • What is θOUT ? AIR 350 n=1.63 θOUT AIR
Using a 600 lines per mm grating • At what angle will I find the m = 2 line for a wavelength λ = 530 nm?