First slide

Young's double slit Experiment

Question

Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8th bright fringe in the medium lies where 5th dark fringe lies in air. The refractive index of the medium is nearly

Moderate

A

1.59
B

1.69
C

1.78
D

1.25

Solution

Position of 8th bright fringe in medium,
$x = \frac{8 λ_{m} D}{d}$
Position of 5th dark fringe in air,
$x^{'} = \frac{(5 - \frac{1}{2}) λ_{air} D}{d} = \frac{4.5 λ_{air} D}{d}$
Given x = x'
$∴ \frac{8 λ_{m} D}{d} = \frac{4.5 λ_{air} D}{d}$
$μ_{m} = \frac{λ_{air}}{λ_{m}} = \frac{8}{4.5} ≃ 1.78$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App