Lecture 21 Notes

Lecture 21 Notes - Recap of last lecture For small the...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Recap of last lecture For small θ the maximas are at 2t = m λ n where λ n = λ 0 /n Maxima for 2t=(m+ ½) λ m=0,1,2… Minima for 2t = m λ Phase shift of λ /2
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
An air wedge between two glass plates Just like the thin film, two waves reflect back from the air wedge in close proximity, interfering as they go. Phase shift of λ /2 Maxima when net phase shift = 2t+ λ /2 =m λ or 2t = (m- ½) λ m=1,2,3,… or 2t=(m+ ½) λ m=0,1,2…
Background image of page 2
Amongst these 4 situations which ones will yield a maxima if 2L = (m+ ½) λ /n 2 A. a B. b C. c D. d 1.4 1.6 1.8 b) 1.8 1.6 L 1.4 c) 1.5 1.3 L 1.4 d) 1.4 1.6 L 1.5 a)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Problem 35.54 There is half-cycle phase change upon reflection on the top surface But not for the bottom, so for constructive interference for λ 1 and λ 2 , where these wavelengths are in glass. The two different wavelengths differ by just one 11 1 12 2 22 2( ) ( ) tm m λλ = += + 21 -value, 1. m mm = 1 1 1 2 1 1 () 2 2 2 2( ) mmm m λ ++  + = = ⇒=   01 1 477.0 nm 540.6 nm 1 17(477.0 nm) 8. 2 8 1334 nm. 2(540.6 nm 477.0 nm) 2 4(1.52) m tt n +  = = = + =   White light reflects at normal incidence from the top and bottom surfaces of a glass plate (n = 1.52). There is air above and below the plate. Constructive interference is observed for light whose wavelength in air is 477.0nm. What is the thickness of the plate if the next longer wavelength for which there is constructive inteference is 540.6nm?
Background image of page 4
Newton’s rings Bright rings when net phase shift = 2t+ λ /2 =m λ or 2t = (m+ ½) λ and dark rings when 2t = m λ m=0,1,2,…
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Newton’s rings
Background image of page 6
You perform the Newton’s Ring experiment with white light instead of monochromatic light, you should see A. No rings B. Larger spacing between rings C. Smaller spacing between rings D. Rings of different color E. Need more information
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
You perform the Newton’s Ring experiment with white light instead of monochromatic light, you should see A. Rings of different
Background image of page 8
Using fringes to test quality control • An optical flat will only display even, concentric rings if the optic is perfectly ground.
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 18

Lecture 21 Notes - Recap of last lecture For small the...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online