In a Young\'s double-slit experiment, a set of parallel slits with a separation
ID: 1583183 • Letter: I
Question
In a Young's double-slit experiment, a set of parallel slits with a separation of 0.104 mm is illuminated by light having a wavelength of 590 nm and the interference pattern observed on a screen 4.50 m from the slits.
(a) What is the difference in path lengths from the two slits to the location of a second order bright fringe on the screen?
m
(b) What is the difference in path lengths from the two slits to the location of the second dark fringe on the screen, away from the center of the pattern?
m
Explanation / Answer
The difference in path lengths from the two slits to the location of a second order bright fringe
on the screen is given by,
path difference = m lamda
= 2* 590 nm
= 1180 nm
=1.18m
(b)
condition for distructive interference is
path difference = ( m+ 1/2) lamda
m =1 for second dark fringe
path difference = ( 1+ 1/2) lamda = 1.5 ( 590) = 885 nm or 0.885 m