The apparent depth of water in a cylindrical water tank of diameter is decreasing at…

PHYSICS · Single correct · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction

Problem

The apparent depth of water in a cylindrical water tank of diameter

2R\,\mathrm{cm}

is decreasing at the rate of

x\,\mathrm{cm/min}

while water is drained at a constant rate. The amount of water drained in

\mathrm{cm^3/min}

is, where

n_1

and

n_2

are the refractive indices of air and water, respectively: (1)

\frac{x\pi R^2n_1}{n_2}

(2)

\frac{x\pi R^2n_2}{n_1}

(3)

\frac{2\pi Rn_1}{n_2}

(4)

\pi R^2x