Explain very briefly what is artificial radioactivity Illustrate giving equation of nuclear reaction.

What do you understand by atomic number $Z$ and mass number $A$? Explain giving examples. If, in a nucleus, the number of protons and neutrons be respectively $p$ and $n$, what will be its atomic number and mass number?

What are ‘isotopes’? Give an example of two isotopic nuclei.

The masses of isotopes are not strictly integral multiples of the mass of a hydrogen atom ${}_1\mathrm{H}^1$ $(Z=1, A=1)$. Why?

Explain the meaning of isobars, giving an example.

What are the changes in the mass number $A$ and atomic number $Z$ of a nucleus due to radioactive disintegration?

Does the neutron to proton ratio in a nucleus increase, decrease or remain same after the nucleus emits an $\alpha$-particle?