This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: terry (ect328) oldhomework 39 Turner (59130) 1 This printout should have 14 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 (part 1 of 2) 10.0 points Light of wavelength 520 nm illuminates two slits of width 0 . 04 mm and separation . 12 mm. How many interference maxima fall within the full width of the central diffraction maxi mum? Correct answer: 5. Explanation: Let : = 520 nm , d = 0 . 12 mm , and w = 0 . 04 mm . The angle of the first diffraction minimum to the width w of the slits of the diffraction grating is sin 1 = w , and the angle corresponding to the m th inter ference maxima is sin m = m d . We require 1 = m , so w = m d m = d w . Therefore the number of fringes in the central maximum is N = 2 m 1 = 2 parenleftbigg d w parenrightbigg 1 = 2 parenleftbigg . 12 mm . 04 mm parenrightbigg 1 = 5 . 002 (part 2 of 2) 10.0 points What is the ratio of the intensity of the third interference maximum to the side of the cen terline (not counting the center interference maximum) to the intensity of the center in terference maximum? Correct answer: 1 . 05556 10 23 . Explanation: The phase difference between the lights at centerline and at third interference maximum is = 2 w sin 3 = 2 w 3 d = 6 w d , so the ratio of the intensities is I 3 I = sin 2 2 2 = sin 6 w 2 d 6 w 2 d 2 = sin 3 w d 3 w d 2 = sin 3 (0 . 04 mm) . 12 mm 3 (0 . 04 mm) . 12 mm 2 = 1 . 05556 10 23 . 003 10.0 points Using a conventional twoslit apparatus with light of wavelength 593 nm, 29 bright fringes per centimeter are observed on a screen 4 m away. What is the slit separation? Correct answer: 6 . 8788 mm. terry (ect328) oldhomework 39 Turner (59130) 2 Explanation: Let : N = 29 cm 1 = 2900 m 1 , = 593 nm = 5 . 93 10 7 m , and L = 4 m . The distance on the screen to the m th and ( m + 1) th bright fringe is y = ( m + 1) L d m L d = L d . Then the number of fringes per unit length is N = 1 y = d L and the slit separation is d = L N = (5 . 93 10 7 m) (4 m) (2900 m 1 ) 1000 mm m = 6 . 8788 mm . 004 10.0 points Two coherent microwave sources that produce waves of wavelength 1 . 5 cm are in the xy plane, one on the y axis at y = 15 cm and the other at x = 1 cm, y = 14 cm. If the sources are in phase, find the differ ence in phase between the two waves from these sources at the origin. Correct answer: 231 . 439 . Explanation: Let : vectorx 1 = ( x 1 , y 1 ) = (0 , 15 cm) , vectorx 2 = ( x 2 , y 2 ) = (1 cm , 14 cm) , and = 1 . 5 cm ....
View
Full
Document
This note was uploaded on 02/17/2010 for the course PHY 59130 taught by Professor Turner during the Fall '09 term at University of Texas at Austin.
 Fall '09
 Turner

Click to edit the document details