Question

Draw a ray diagram showing the path of rays of light when it enters with oblique incidence
(A) from air into water
(B) from water into air.

Answer 1

Hint: The phenomenon of refraction occurs when light bends as it travels from one medium to another. Because the speed of light varies in different mediums, refraction is greater in denser materials and vice versa.

Complete Step By Step Answer:
When a ray of light enters the water with an oblique incidence from the air, it passes from an optically rarer medium to an optically denser medium here, and its velocity slows, bending the incident light towards the normal.

 $\mathrm{\angle }i$ is the angle of incidence and $\mathrm{\angle }r$ is the angle of refraction from the normal. We see in this case angle of incidence is greater than the angle of refraction
When a ray of light passes through water and into the air at an oblique angle, it passes from an optically denser medium here water to an optically rarer medium here air, increasing the velocity of light, which bends the incident light away from the normal.

 $\mathrm{\angle }i$ is the angle of incidence and $\mathrm{\angle }r$ is the angle of refraction from the normal. In this case the angle of incidence is smaller than the angle of refraction.

Note:
When light ray enters in a medium from rarer to denser or denser to rarer perpendicularly that is making ${90}^{\circ }$ angle with the water surface, no refraction takes place as the angle of incidence is zero so the angle of refraction will also be zero.