For making solar cookers, why are concave reflectors used?

A solar cooker uses the energy of sunlight to pasteurize drinks or cook food. Many of these cookers on the market today are relatively inexpensive thanks to the creative use of the materials used to make these units. read more

A concave lens is not used in a solar furnace. A concave mirror may be. The key is the attempt to form a real image of the sun, where not only its light but, more important, its heat is concentrated in a small area. read more

You can design many solar reflectors for solar cookers, and other things that need reflectors, without doing any mathematics. In fact you can often get by knowing just two things: 1. read more