Question

Arrange the following radiations in terms of increasing order of their ionizing power:
(A). X-rays
(B). Beta-particles
(C). Alpha-particles
(D). Gamma-rays
Choose the correct answer from the options given below:

• A. (A), (B), (C), (D)
• B. (A), (B), (D), (C)
• C. (B), (A), (D), (C)
• D. (C), (B), (A), (D)

Hint:

Remember that the more massive and charged the particle is, the greater is its ionizing power and the lower its penetration power, which is why alpha particles are the strongest ionizers, however, they are stopped by a sheet of paper.

Answer 1

The Correct Option is B

Ionizing power refers to the ability of radiation to remove electrons from atoms or molecules, creating ions. The ionizing power depends on the energy and the charge of the radiation.
• Alpha particles (α): These are the most massive (consisting of two protons and two neutrons) and are doubly charged (+2e). However, their ionizing power is high, but their penetration is low because of their high charge and large mass.
• Beta particles (β): These are high-energy electrons (or positrons) and have a charge of −1e or +1e. They are much smaller than alpha particles and more penetrating, with moderate ionizing power.
• X-rays: These are high-energy electromagnetic radiation with no charge. Their ionizing power is less than charged particles because of their lower interaction probability with matter than charged particles. Their penetration is higher than beta particles.
• Gamma rays (γ): These are the highest energy electromagnetic radiation, with no charge. Their penetration power is much higher than X-rays, and they are highly ionizing.
Based on the charge, mass and energy of these radiations, we can order their ionizing power as follows: X-rays ¡ Beta particles ¡ Gamma rays ¡ Alpha particles. Therefore in terms of increasing order of ionizing power: X-rays, Beta particles, Gamma rays and Alpha particles. In terms of options the correct order is: (A) X-rays, (B) Beta particles, (D) Gamma rays, (C) Alpha particles