A solar cooker uses a mirror to concentrate sunlight onto a vessel. Which type of mirror is used and what property makes it suitable?

Correct Option: A concave mirror because it focuses parallel sunlight to a single point

Step-by-Step Explanation:

1. Understanding the Purpose of a Solar Cooker:
A solar cooker works by collecting sunlight and converting it into heat energy to cook food. To attain high temperatures efficiently, sunlight coming from a large area needs to be concentrated onto a smaller area, specifically onto the cooking vessel.

2. Analyzing the Optical Properties of Concave Mirrors:
Sunlight reaching the Earth travels in essentially parallel rays because the Sun is extremely far away. A concave mirror is a spherical mirror whose reflecting surface curves inward.

3. Focusing Effect:
When parallel rays of light fall on a concave mirror, they reflect and converge at a single common point on the principal axis called the principal focus ($F$). Because it converges light rays, a concave mirror is also known as a converging mirror.

4. Application in Solar Cookers:
By placing the cooking vessel at the focal point of the concave mirror, maximum solar radiation and thermal energy are concentrated directly onto the vessel, allowing it to heat up rapidly and effectively.

Therefore, a concave mirror is used because it focuses parallel rays of sunlight to a single point, generating high heat for cooking.