Total Internal Reflection: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Total Internal Reflection. Understanding the underlying formula is key to arriving at the correct answer below:

Critical angle is given by $\sin \theta_c = \frac{\mu_{rarer}}{\mu_{denser}} = \frac{v_{denser}}{v_{rarer}}$.
The speed of light is lower in the denser medium, so $v_{denser} = 1.5 \times 10^8 m/s$ and $v_{rarer} = 2.0 \times 10^8 m/s$.
$\sin \theta_c = \frac{1.5 \times 10^8}{2.0 \times 10^8} = 0.750$, leading to $\theta_c = \sin^{-1}(0.750)$.