Q 12-09-009NEETNEET 2023Top questionMedium
Light travels a distance $x$ in time $t_1$ in air and $10x$ in time $t_2$ in another denser medium. What is the critical angle for this medium?
Answer: (D) $\sin^{-1}\left(\dfrac{10t_1}{t_2}\right)$
Speed in air: $c = \dfrac{x}{t_1}$. Speed in the medium: $v = \dfrac{10x}{t_2}$.
$$n = \frac{c}{v} = \frac{x/t_1}{10x/t_2} = \frac{t_2}{10t_1}$$
$$\sin C = \frac{1}{n} = \frac{10t_1}{t_2} \;\Rightarrow\; C = \sin^{-1}\left(\frac{10t_1}{t_2}\right)$$
Solution by Sreeraj P, M.Sc Physics