Question

Which mirror is used in the searchlights?
A. concave
B. convex
C. plane
D. Plano convex

Answer 1

Hint: In search lights, we need an intense parallel beam of light and it depends a lot on the mirror’s capability to concentrate the beam of light. For this we need a curved mirror that can make all the light rays parallel to the principal axis as the mirror captures the majority of the light when the bulb is placed on the focus.

Complete Step-by-Step solution:
Concave mirror is a converging mirror that simply converges the light rays falling on it at the focus. It has a reflecting surface that is recessed inward i.e. away from the incident light. Concave mirror has the property to simply converge the light rays inward at one focal point. Concave mirror is basically used in focusing light.

For the searchlights, we use the concave mirror because we need a mirror that basically focuses the light and when the bulb is placed at the focus it diverges the light rays to produce an intense parallel beam of light and the concave mirror can do that in a very good way.
Hence, we can say that a concave mirror is used in the searchlights.
\[\therefore \] Option A. concave is the correct answer.

Note- For the searchlights, in a nutshell just put the lighted bulb at the focus of the concave mirror reflector such that the diverged rays of light are collected by the concave reflection and then reflected to generate an intense parallel beam of light.