Explain the use of concave mirror as solar concentrators with the help of a ray diagram.

Concave mirrors can concentrate parallel light rays (from distant objects e.g. Sun) at the focus.

This property of the concave mirror is used in solar concentrators (for e.g. solar cookers) as high concentration of the sun rays generate high amount of heat which farther can be used as a heat source. The diagram below shows the concentration of sun rays

This solar concentrator can be used as a solar cooker.