Question

The efficiency of the solar cooker can be increased by placing which kind of mirror.

• A. Convex Lens.
• B. Plane Mirror.
• C. Convex Mirror.
• D. Concave Mirror

Answer 1

The correct option is B

Plane Mirror.

Explanation for correct option:

In the case of option B,

1. A solar cooker is housed in a box made of insulating material with blackened inner surfaces.
2. A glass sheet covers the top.
3. The efficiency of the solar cooker can be increased by placing an inclined plane mirror with a glass top to trap more solar energy.
   

Explanation for incorrect options:

1. In the case of option A, convex lenses are used in eyeglasses for correcting farsightedness, where the distance between the eye's lens and retina is too short, as a result of which the focal point lies behind the retina.
2. In the case of option C, convex mirrors are curved mirrors with a reflective surface that bulges out towards the light source. This protruding surface reflects light in all directions and is not used to focus light.
3. In the case of option D, the reflective surface of a concave mirror is curved inward and away from the light source. Concave mirrors focus light inward to a single focal point.

Hence, option (B) is correct.