Question

Young's double slit experiment is performed in a liquid. the $10th$ bright fringe in liquid lies where $6th$ dark fringe lies in air. the refractive index of the liquid is approximately

• A. 1.2
• B. 1.6
• C. 1.5
• D. 1.8

Answer 1

The correct option is B 1.6

Formula,

for liquid,

$y=\frac{10\left(\frac{\lambda }{\mu }\right)D}{d}$

for vaccum,

$y=\frac{6\lambda D}{d}$

given,

$\frac{10\left(\frac{\lambda }{\mu }\right)D}{d}=\frac{6\lambda D}{d}$

$\mu =\frac{10}{6}=1.67$