Refraction by Plane Surfaces: Practice Problem & Solution

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Refraction by Plane Surfaces. Understanding the underlying formula is key to arriving at the correct answer below:

The speed of light in a given medium is related to the refractive index by $v = \frac{c}{n}$ . Given the speed of light in vacuum $c = 3 \times 10^8 m/s$ and the refractive index of water $n = 1.33 = \frac{4}{3}$ . We find $v = \frac{3 \times 10^8}{4/3} = \frac{9 \times 10^8}{4} = 2.25 \times 10^8 m/s$ .