Light Energy

A visitor to quora.com writes:  Please give me an example of light energy.  

All light is energy.  Visible light is a tiny part of the electromagnetic spectrum, i.e., electric and magnetic fields that oscillate back and forth, in this case between 430–770 trillion times a second. The higher the frequency, the higher the energy, so “light” that is invisible to the human eye is because its frequency is too high, e.g., X-rays and gamma rays, have much greater energy levels, and therefore cause injury to living tissue.  That’s why they are used as cancer treatment; they are a type of radiation that damages whatever cells they collide with, and since cancer cells can’t repair themselves, they die.