光的反射和折射

A ray of light travels in air and strikes a semi-circular glass block at an angle of incidence $42^\circ$. The critical angle of the glass is $42^\circ$. Which of the following diagrams best shows the subsequent path(s) of the ray ?

The diagram shows a light ray travelling from liquid to air. Find the refractive index of the liquid.

The refractive indices of water and glass are $1.33$ and $1.5$ respectively. In which of the following cases will total internal reflection occur ?

A ray of light passes from air into a glass block. Which of the following ray diagrams is/are correct ? (Given that the critical angle of glass is $42^\circ$.)

In the diagram shown, a light ray passes from medium $Y$ to medium $X$ and emerges to medium $Y$ again. The refractive index of medium $X$ is smaller than that of medium $Y$. Which of the following represents the path of the emergent ray ?

As shown in the diagram, the apparent position of the aeroplane seen by the diver at the bottom of the small pond is at

In the diagram, $PQR$ represents the path of a ray of light incident on a semi-circular glass slab. $Q$ is the centre of the slab. Which of the directions $W$, $X$, $Y$ or $Z$ correctly indicates the subsequent path of the refracted ray ?