Question

Choose the correct option in which the ionization power of alpha(α), beta(β) and gamma(γ) particles is arranged correctly.

• A. α < β < γ
• B. γ > β, and α = 0
• C. α > β < γ
• D. γ < β < α

Answer 1

The correct option is D

γ < β < α

Alpha particles are strongly ionising but can be stopped even by a thick paper. The charge of an alpha particle is $+2e$. Thus, they are most effective at knocking out electrons.

Beta particles are fast moving electrons. Among the three, they have medium ionizing ability and medium penetrating power.

Gamma rays have very high penetrating power and very poor ionising power. So, the correct order is γ < β < α.