A horizontal parallel beam of light passes through a vertical convex lens of focal length $20 \mathrm{~cm}$ and is then reflected by a tilted plane mirror so that it converges to a point $\mathrm{I}$. The distance $\mathrm{PI}$ is $10 \mathrm{~cm}$.
$\mathrm{M}$ is a point at which the axis of the lens intersects the mirror. The distance $\mathrm{PM}$ is $10 \mathrm{~cm}$. The angle which the mirror makes with the horizontal is

• A

  $15^{\circ}$
• B

  $30^{\circ}$
• C

  $45^{\circ}$
• Correct answer
  D

  $60^{\circ}$

Solution

$60^{\circ}$

Hence, the correct answer is option: 'D'.