question_answer

A diver at a depth of 12 m in water \[\left( \mu =\frac{4}{3} \right)\] sees the sky in a cone of semivertical angle

A)  \[{{\sin }^{-1}}\left( \frac{4}{3} \right)\]                               

B)  \[{{\tan }^{-1}}\left( \frac{4}{3} \right)\]

C)  \[{{\sin }^{-1}}\left( \frac{3}{4} \right)\]                               

D)  \[\text{9}{{\text{0}}^{\text{o}}}\]

Correct Answer: C

Solution :

                 We can represent this diagrammatically as Thus, we see that \[c={{\sin }^{-1}}\left( \frac{1}{\mu } \right)={{\sin }^{-1}}\left( \frac{3}{4} \right)\]