Coherent light that contains two wavelengths, 660 nm and 470 nm , passes through
ID: 1455422 • Letter: C
Question
Coherent light that contains two wavelengths, 660 nm and 470 nm , passes through two narrow slits with a separation of 0.330 mm and an interference pattern is observed on a screen which is a distance 5.30 m from the slits.
Part A
What is the distance on the screen between the first-order bright fringe for each wavelength?
Coherent light that contains two wavelengths, 660 nm and 470 nm , passes through two narrow slits with a separation of 0.330 mm and an interference pattern is observed on a screen which is a distance 5.30 m from the slits.
Part A
What is the distance on the screen between the first-order bright fringe for each wavelength?
Explanation / Answer
= 660 nm = 6.6 x 10^-7 m
= 470 nm = 4.7 x 10^-7 m
d = 0.330 mm = 3.3 x 10^-4 m
L = 5.30 m
use formula : y = k ( L)/d . . . . . (k = order of bright fringe)
for : = 6.6 x 10^-7 m (the first-order k = 1)
=> y= 1 {(6.6 x 10^-7) (5.30)} / 3.3 x 10^-4
=> y= 0.0106 m = 10.6mm
for : = 4.7 x 10^-7 m . . . . . . (the first-order k = 1)
=> y= 1 {(4.7 x 10^-7 ) (5.30)} / 3.3 x 10^-4
=> y=7.548 mm
so, the distance on the screen between the first-order bright fringe for each wavelength :
=> y = y- y
=> y = 10.6 - 7.548= 3.052 mm