A small coin is resting on the bottom of a beaker filled with a liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface (see figure). How fast is the light travelling in the liquid?

Question

A small coin is resting on the bottom of a beaker filled with a liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface (see figure). <img class="img-fluid question-image" alt="Question" src="https://cdn.tardigrade.in/q/nta/p-nximyusaprqxqgpi.jpg" /> How fast is the light travelling in the liquid? (A) 1.2× 108ms- 1 (B) 1.8× 108ms- 1 (C) 2.4× 108ms- 1 (D) 3.0× 108ms- 1

Tardigrade Admin · Accepted Answer

sinθ C=(μ R/μ D)=(vD/vR) (6/10)=(vD/3 × 108) vD=1.8× 108ms- 1

Q. A small coin is resting on the bottom of a beaker filled with a liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface (see figure).

How fast is the light travelling in the liquid?

$1.2 \times 1 0^{8} m s^{- 1}$

$1.8 \times 1 0^{8} m s^{- 1}$

$2.4 \times 1 0^{8} m s^{- 1}$

$3.0 \times 1 0^{8} m s^{- 1}$

$s in θ_{C} = \frac{μ _{R}}{μ _{D}} = \frac{v _{D}}{v _{R}}$
$\frac{6}{10} = \frac{v _{D}}{3 \times 1 0 ^{8}}$
$v_{D} = 1.8 \times 1 0^{8} m s^{- 1}$

Q. A small coin is resting on the bottom of a beaker filled with a liquid. A ray of light from the coin travels upto the surface of the liquid and moves along its surface (see figure). How fast is the light travelling in the liquid?

1.2×108ms−1

1.8×108ms−1

2.4×108ms−1

3.0×108ms−1