In Young's double slit experiment the y-coordinates of central maxima and 10th maxima are `2cm` and `5cm` respectively. When the YDSE apparatus is immersed in a liquid of refractive index `1.5` the corresponding y-coordintates will be

Options

A. (a) `2cm`, `7.5cm`
B. (b) `3cm`, `6cm`
C. (c) `2cm, 4cm`
D. (d) `4//3cm`, `10//3cm`

Answer

C

Explanation

Fringe width `betaprolambda`. Therefore, `lambda` and hence `beta` decrease `1.5` times when immersed in liquid. The distance between central maxima and `10^(th)` maxima is `3cm` in vacuum. When immersed in liquid it will reduce to `2cm`. Position of central maxima will not change while `10^(th)` maxima will be obtained at `y=4cm`.