Question

what is radioactivity?

Answer 1

The energy which is evolved when nucleus gets busted.

Answer 2

it is similar to electro magnetic radiation. Not in characteristics but in observation.

Answer 3

spontaneous disintegration of nucleus with liberation of energy :)

Answer 4

Radioactive decay, also known as nuclear decay or radioactivity, is the process by which a nucleus of an unstable atom loses energy by emitting particles of ionizing radiation. A material that spontaneously emits this kind of radiation - which includes the emission of energetic alpha particles, beta particles, and gamma rays - is considered radioactive.