How/why is light an electromagnetic radiation?

A2A.: Electromagnetic radiation is massless, but it does weigh, i.e., interact with the gravitational field, depending on how much energy & momentum it carries. That is, its mass† vanishes. read more

Light is called an 'electromagnetic wave' for historical reasons* in the following sense: It turned out that the effects of visible light and other radiation can be calculated using Maxwell's equations, which are also used to model the behaviour of electrically charged particles. read more

Electromagnetic (EM) radiation is a form of energy that is all around us and takes many forms, such as radio waves, microwaves, X-rays and gamma rays. Sunlight is also a form of EM energy, but visible light is only a small portion of the EM spectrum, which contains a broad range of electromagnetic wavelengths. read more

electromagnetic radiation: Visible radiation Visible light is the most familiar form of electromagnetic radiation and makes up that portion of the spectrum to which the eye is sensitive. This span is very narrow; the frequencies of violet light are only about twice those of red. read more