A radioactive source emits three types of radiations R, S and T. The diagram given below shows an experimental set up to study the penetrating properties of R, S and T. Which type of radiation are R, S and T ?

(a)	R - α - particle	S - β - particle	T - γ - rays
(b)	R - α - particle	S - γ - rays	T - β - particle
(c)	R - β - particle	S - α - particle	T - γ - rays
(d)	R - γ - rays	S - β - particle	T - α - particle

1. Option (a)
2. Option (b)
3. Option (c)
4. Option (d)

Option (b)

Reason — Increasing order of penetrating power of different radiations is : α - particle < β - particle < γ - rays