Question

Compare the ionising powers of $\alpha :\beta :\gamma $ particles.
$\text{A}\text{. }{{10}^{2}}:{{10}^{4}}:1$
$\text{B}\text{. }{{10}^{1}}:{{10}^{4}}:{{10}^{2}}$
$\text{C}\text{. }{{10}^{4}}:{{10}^{2}}:1$
 D. None of these

Answer 1

Hint: When the radiations interact with the atoms, the atoms lose electrons and thus are ionised. The greater the ionising power of the radiation, more is the process of ionising. As a result, more damage is caused to the atoms. The ionising power is directly proportional to the mass of the particle.

Complete answer:
Let us first understand what $\alpha :\beta :\gamma $ particles are. When one nucleus gets converted into another nucleus to attain stability, either an alpha ($\alpha $), beta ($\beta $) or gamma ($\gamma $) particles are released. These are actually radiations.
These particles have high energies. Therefore, these particles are harmful in nature. When either of these particles strike the surface of a tissue, they cause damage to the atoms. The extent of the damage is understood by the ionising power of the particles.
When the radiations interact with the atoms, the atoms lose electrons and thus are ionised. The greater the ionising power of the radiation, more is the process of ionising. As a result, more damage is caused to the atoms.
The ionising power is directly proportional to the mass of the particle.
Among the three, alpha particles have the largest mass, followed by beta particles and then gamma.
Therefore, alpha particles have the maximum ionising power and the gamma radiation has the least ionising power. The ionising power of beta particles in between the two values.

So, the correct answer is “Option C”.

Note:
Other than the ionising power, we also study the penetration power. Penetration power is the ability of the radiation to penetrate a body.
More the ionising power of the radiation less is its penetration power and vice versa.
Therefore, gamma radiations have the maximum penetration power and the alpha particles have the least penetrating power.