Question

Among electron, proton, neutron and $\alpha$ - particle, the maximum penetration capacity is for:

• A. Electron
• B. Proton
• C. Neutron
• D. $\alpha$ - particle

Answer 1

Answer: (C)

Neutron

$\alpha$ particle comprises of 2 protons and 2 neutrons, which have 4 times higher mass than neutrons, and thus low penetration power.

Beta particles are much smaller and more penetrating than alpha particles, but their range in tissue is still limited.
Due to their large mass and being chargeless in nature, neutrons have high kinetic energy and thus, high penetration power.