Answer: The correct option is B ( a small charged particle.
Explanation:
Radioactive decay occurs when an atom absorbs heat energy from its surrounding which results to an unstable nucleus splitting up or breaking up into one or more other elements. There are three types of radioactive decay which includes:
--> Alpha decay
--> Beta decay
--> Gamma decay.
Beta decay: in some radioactive substances, the nucleus, when it disintegrated, emits beta- particles (β - particles). Their deflection in magnetic field, their absorption in various substances and the tracks they make in a cloud chamber are all identical with cathode rays, that is, with fast moving electrons.
Beta decay occurs when, in a nucleus with too many protons or too many neutrons, one of the protons or neutrons is transformed into the other. In beta minus decay, a neutron decays into a proton, an electron, and an antineutrin.
In beta plus decay, a proton decays into a neutron, a positron, and a neutrino
The β - particles come from the neurons in the nucleus, each neutron, in emitting a β-particles, turns into a proton. Thus the emission of a β-particles makes no difference to the mass number of a nucleus, but changes the charge carried by the nucleus and causes the atomic number to advance by one unit. Therefore, small charged particles are emitted during beta decay.