Question

Which of the following types of mirror is used in the headlight of a car ?

• A. Convex mirror
• B. Concave mirror
• C. Plane mirror
• D. None of these

Hint:

Remember the key applications: Concave mirrors are used where light needs to be concentrated (headlights, solar cookers, shaving mirrors). Convex mirrors are used where a wide field of view is needed (rear-view mirrors in vehicles, security mirrors).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The purpose of a car headlight is to project a strong, parallel beam of light to illuminate the road over a long distance. The choice of mirror depends on its ability to produce such a beam.

Step 2: Detailed Explanation:
A concave mirror has the property that if a light source is placed at its principal focus (F), the rays of light, after reflection from the mirror's surface, travel out as a parallel beam.
This is exactly the requirement for a car headlight. The bulb of the headlight is positioned at the focus of a concave reflector. This ensures that the light produced is directed forward as a powerful, parallel beam, providing maximum illumination of the path ahead.
A convex mirror would scatter the light, and a plane mirror would simply reflect it without focusing it into a beam.

Step 3: Final Answer:
A concave mirror is used as a reflector in the headlight of a car.