Question

A convex of lens of focal length 15 cm is placed on a plane mirror. An object is placed at 30 cm from the lens. The image is :

• A. Real, at 30 cm in front of the mirror
• B. Real, at 30 cm behind the mirror
• C. Real, at 10 cm in front of the mirror
• D. Virtual ,at 10 cm behind the mirror

Answer 1

Answer: (C)

Real, at 10 cm in front of the mirror

Answer 2

: $\frac { 1 } { F } = \frac { 1 } { f _ { l } } + \frac { 1 } { f _ { p . m } } + \frac { 1 } { f _ { 1 } } = \frac { 2 } { f _ { 1 } } + \frac { 1 } { \infty } \Rightarrow F = \frac { 15 } { 2 } m$

$\therefore$Image is real, 10 cm in front of mirror.