Question

How is a ray of light different from a beam of light?

Answer 1

Ray of light is just a single light Ray when you combine them they are collectively called a beam of light

Answer 2

The terms ‘ray’ and ‘radiation’ mean entities that carry energy through space.

One example is electromagnetic radiation: radio, infrared, visible light, ultraviolet, X-rays, gamma rays which involve photons that have no mass. Further examples are alpha and beta rays which involve particles which do have mass.

The term ‘beam’ is usually used to describe a horizontal column of radiation.

So ‘ray’ does not say how spread out the radiation is, it could be spreading out in all directions, whereas the term ‘beam’ is used when the radiation is restricted to a column.