Question

Screen 84 GO In Figure 35-50, two isotropic point sources S, and S, emit light in phase at wavelength 1 and at the same amplitude. The sources are separated by distance d = 6.001 on an x axis. A viewing screen is at distance D = 20.0, from S, and par- -d-to- allel to the y axis. The figure shows two rays reaching point P on the screen, at height yp. (a) At what value of yp do the rays have the minimum possible phase differ. ence? (b) What multiple of a gives that minimum phase diffe ence? (c) At what value of yp do the rays have the maximum possi ble phase difference? What multiple of 1 gives (d) that maximum phase difference and (e) the phase difference when yp = d? (f) When yp = d, is the resulting intensity at point P maximum, mini- Figure 35-50 Problem 84.

Answer 1

(6) when both Doa (a) The minimum path difference occurs When both rays are nearly vertical, so the point will be at infinity (0) When both days are nearly virtital, ene is to path difference between rays. So at y=0, phase difference Do = dł (path difference) Do - o (e) at Yp5, both rays are horizontal so at Yp=0 (or at origin), says have maximum possible phase difference. d) Maximum phase difference, DO = 2t sx 00= 2 (62) = 120 grad. "Ang. ce) By pythagore about your o 5580 tie aut y =d, phase difference is 5.80 wavelength any

(f) Since in partce) phase difference 80 e in closer to 6 Constructive interferce) than 5 / (destructive interference) so resulting intensity at Point P will be intermediate but closer to maximum