Question

A person AB of height 170 cm is standing in front of a vertical plane mirror. His eyes are at height 164 cm from ground. At what distance from P should a hole be made in the mirror so that he cannot see the top of his head?

Options

• 167 cm

• 161 cm

• 163 cm

• None of these

Answer 1

167 cm

Explanation:

A beam from the top of the head should enter the eye as depicted in order to see the top of the head. The head cannot be seen if the mirror's point of incidence is struck. The hole on the mirror must be punched at 3 cm from the top end according to the ray diagram.