Question

1. explain why a pencil looks bent when placed in a glass of water.

Explanation:

This phenomenon occurs due to the refraction of light. When light travels from air (a less dense medium) into water (a denser medium) at an angle, it changes its direction (bends towards the normal). The part of the pencil under water reflects light that refracts at the air - water interface. Our eyes perceive the light as coming from a straight - line path (extrapolating the refracted light backwards), which makes the pencil appear bent at the water - air boundary.

Answer:

A pencil looks bent in water due to light refraction. Light from the submerged part bends at the air - water interface. Our eyes follow the refracted light's apparent path, creating the bent - pencil illusion.