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. `2cm, 7.5 cm`
B. `3 cm, 6cm`
C. `2 cm, 4 cm`
D. `4//3 cm, 10//3 cm`

Answer

C

Explanation

Fringe width `beta=(Dlambda)/d`
i.e., `beta prop lambda`
So, wavelength `lambda` and hence fringe width `beta` decreases `1.5` times when immersed in liquid The distance between central maxima and 10 th maxima is 3 cm 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=4 cm