Light therapy is a powerful tool to deliver benefits to living tissues and organisms. Visible light penetrates tissues to a depth of about 8−10mm.
It is very beneficial in treating problems close the surface such as wounds, cuts, scars muscle ache etc.
Infrared light penetrates to a depth of about 30−40mm which makes it more effective for use of treatment of muscle ache.
While microwaves are used for purpose of cooking food.
Ultraviolet light is used in fluorescent lamps, pest control etc.
Excess exposure is harmful for human skin.
X-rays are used for diagnostic medical imaging and crystallography.