JEE Main201912 Jan 2019Morning ShiftPhysicsRay OpticsActual
A point source of light, S is placed at a distance L in front of the center of plane mirror of width d which is hanging vertically on a wall. A man walks in front of the mirror along a line parallel to the mirror, at a distance 2L as shown below. The distance over which the man can see the image of the light source in the mirror is:
Options
- A3 d
- B2 d
- Cd
- Dd 2
Correct answer
A. 3 d
Step-by-step solution
By similar triangles Δ A E C ~ Δ I H A y 2 L = d 2 L (by properties of similar triangles) ⇒ y = d ∴ Total distance C D = y + d 2 + d 2 + y = 3 d