Critical angle from the speeds or refractive indices of two media

1. A.
   $10^{\circ}$
2. B.
   $20^{\circ}$
3. C.
   $30^{\circ}$
4. D.
   $60^{\circ}$

Tap an option to check your answer.

1. A.
   $\theta = \sin^{- 1}\left( \frac{3}{4} \right)$
2. B.
   $\theta > \sin^{- 1}\left( \frac{2}{3} \right)$
3. C.
   $\theta < \sin^{- 1}\left( \frac{3}{4} \right)$
4. D.
   $\theta > \sin^{- 1}\left( \frac{3}{4} \right)$

Tap an option to check your answer.

1. A.
   $\tan^{- 1}\left( \frac{3}{\sqrt{7}} \right)$
2. B.
   $\tan^{- 1}\left( \frac{2}{3} \right)$
3. C.
   $\cos^{- 1}\left( \frac{3}{4} \right)$
4. D.
   $\sin^{- 1}\left( \frac{2}{3} \right)$

Tap an option to check your answer.

1. A.
   $5 \times 10^{7}\text{ }m/s$
2. B.
   $2.12 \times 10^{8}\text{ }m/s$
3. C.
   $3.12 \times 10^{7}\text{ }m/s$
4. D.
   $\sqrt{2} \times 10^{8}\text{ }m/s$

Tap an option to check your answer.

1. A.
   $\sqrt{2}:1$
2. B.
   $1:2$
3. C.
   $1:\sqrt{2}$
4. D.
   $2:1$

Tap an option to check your answer.

1. A.
   $\cot^{- 1}\left( \frac{3}{\sqrt{13}} \right)$
2. B.
   $\sin^{- 1}\left( \frac{9}{8} \right)$
3. C.
   $\tan^{- 1}\left( \frac{8}{\sqrt{17}} \right)$
4. D.
   $\cos^{- 1}\left( \frac{8}{9} \right)$

Tap an option to check your answer.