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?

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? (A) 167 cm (B) 161 cm (C) 163 cm (D) None of these

Tardigrade Admin · Accepted Answer

To see top of head, a ray should start from top of head and enter the eye as shown. If that point of incidence of mirror is punched, the head cannot be seen. From the ray diagram the hole has to be punched on mirror at 3 cm from top end

Q. A person $A B$ of height $170 c m$ is standing in front of $a$ vertical plane mirror. His eyes are at height $164 c m$ 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?

$167 c m$

$161 c m$

$163 c m$

None of these

To see top of head, a ray should start from top of head and enter the eye as shown. If that point of incidence of mirror is punched, the head cannot be seen. From the ray diagram the hole has to be punched on mirror at $3 c m$ from top end

Q. A person AB of height 170cm is standing in front of a vertical plane mirror. His eyes are at height 164cm 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?

167cm

161cm

163cm