A nucleus of stable phosphorus has 15 protons and 16 neutrons.

(a) What is it's atomic number and mass number?

(b) The nucleus of radio phosphorous has one neutron more than the stable nucleus. What will be it's atomic number and mass number?

(c) What will be the atomic number and mass number of new nucleus formed by decay of a β-particle by the radio phosphorus in part (b)?

An element P disintegrates by α emission and the new element suffers two further disintegrations, both by β emission, to form an element Q. Explain the fact that P and Q are the isotopes.

The mass of an electron is :

1. 1.6725 x 10^-27
2. 1.6725 x 10^-31
3. 1.6748 x 10^-31
4. 9.1 x 10^-31

The particle used in nuclear fission for bombardment is:

1. α particle
2. proton
3. β particle
4. neutron