Question

Which of the following has the highest penetrating power?
A. Alpha rays
B. Gamma rays
C. Beta rays
D. All have same penetration power

Answer 1

Hint: The penetrating power of a certain radiation depends on the energy and the ionizing power of that radiation. The radiation penetrates the material up to the point where it loses all its energy ionizing the material.

Complete step-by-step answer:
A radioactive nucleus emits three types of radiation:
Alpha rays: They are basically helium nuclei. These rays have high ionization power. As they travel through a material, they quickly ionize the medium losing their energy due to which they are unable to penetrate to more than a few centimetres within the material. They have the highest ionizing power and least penetration power. They are harmful if the particular radioactive material is in direct contact with the human skin.

Beta rays: These are either electrons or positrons produced in the nucleus of a radioactive nucleus. Their ionizing power is greater than that of alpha rays. Due to which they are able to penetrate deeper in the material and are more harmful than alpha rays and are able to penetrate deeper than alpha rays.

Gamma rays: They are photons emitted by an excited nuclei returning to its ground state. They have the lowest ionizing power due to which these rays can penetrate deeper than other rays and prove to be dangerous to humans as they have the highest penetrating power.

Therefore, the correct answer is option B.

Note: The radioactive radiation can damage the human DNA. These radiation transfer their energy to the material as they propagate which can alter the human DNA, leading to abnormalities in body parts or cancers in the exposed regions.