Out of the following, which one is not emitted by a natural radioactive substance?
Electrons
Electromagnetic radiations
Helium nuclei with charge equal to that of two protons
Neutrons
In a sample of radioactive material, what percentage of the initial number of active nuclei will decay during one mean life .......... $\%$
The rate of disintegration of a fixed quantity of a radioactive element can be increased by
Radioactivity is
$\beta$- rays emitted by a radioactive material are
The particle that possesses half integral spin as