Answer 1

A concave mirror is used in a solar cooker as it uses heat of the sunlight to cook food. The mirror focuses all the incident sunlight at a point. The temperature at that point increases, thereby cooking and heating the food placed at that point.

Answer 2

A concave mirror is best suited for use in a solar cooker because it converges a large amount of the sun's heat rays at its focus, because of which a high temperature is produced in the focus area.