Question

In a biprism experiment, D = 1 m, `lambda` = 6000 Å. When a convex lens is interposed between the biprism ru1d the eyepiece, then the distance between the images of the slits given by the Jens at two positions are 1.5 mm and 6.0 mm. The fringe width will be ______.

Options

•  0.2 mm

• 0.25 mm 

• 0.30 mm

• 0.45 mm

Answer 1

In a biprism experiment, D = 1 m, `lambda` = 6000 Å. When a convex lens is interposed between the biprism ru1d the eyepiece, then the distance between the images of the slits given by the Jens at two positions are 1.5 mm and 6.0 mm. The fringe width will be 0.25 mm. 

Explanation:

d= `sqrt ("d"_1"d)= sqrt(1.5 xx 6 xx 10^-6) = 3 xx 10 ^-3 `m

∴ W ` = (lambda "D")/"d" = (6000 xx 10^-10 xx 1)/(3 xx 10^-3)`

= `2 xx 10^-4` m = 0.2 mm