Q. What do you mean by electro-magnetic radiation?

In the untimely twentieth century scientists accepted the idea that an atom consisted of a massive positively charged nucleus surrounded by negatively charged electrons. Additional explanation of the atom's electron arrangement came from research involving light and its interaction with matter.

Wave nature of light observable light is part of a range of electro-magnetic radiation a form of wave energy that travels through empty space and is propagated in the form of alternating electric and magnetic fields. Gamma rays, X rays and radio waves are other examples of electromagnetic radiation.