Refraction by Plane Surfaces: Practice Problem & Solution

Solution Explained:

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:

Velocity of light in the window glass is $v = \frac{c}{\mu} = \frac{3 \times 10^8}{3/2} = 2 \times 10^8 m/s$.
Thickness is $t = 4 mm = 4 \times 10^{-3} m$.
Time taken is $T = \frac{t}{v} = \frac{4 \times 10^{-3}}{2 \times 10^8} = 2 \times 10^{-11} s$.