In Geiger Marsden alpha scattering experiments, a beam of alpha particles emitted from \( {}^{214}_{83}\mathrm{Bi} \) were directed to strike a gold foil and various observations were made. Now answer the following questions.
The penetration power of \( \alpha \), \( \beta \) and \( \gamma \) are related as:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \( \gamma \gt \beta \gt \alpha \)
The penetrating power of a radiation is the reverse of its ionising power: the more a radiation ionises the matter it passes through, the faster it loses its energy and the sooner it is stopped.
\( \alpha \) particles: heavy and doubly charged, ionise strongly, stopped by a sheet of paper
\( \beta \) particles: light and singly charged, stopped by a few millimetres of aluminium
\( \gamma \) rays: uncharged photons, ionise weakly, need several centimetres of lead
So the penetrating power is in the order \( \gamma \gt \beta \gt \alpha \).