Describe two reasons why an alpha particle is less penetrating than a beta or gamma particle.

1. Heavy mass

2. greater charge

Explanation:

An alpha particle has two protons and two neutrons. It has +2 e charge. It is a heavy mass particle. Thus, when it tends to penetrate even a thin sheet, it loses its energy very quickly because of its interaction with the material particles.

Beta particle is a high energy electron or positron. It carries 1 unit charge and has very less mass in comparison to an alpha particle. Thus, it has more penetrating power than alpha particle.

A gamma particle is charge less and mass less highly energetic particle. Thus, it has highest penetrating power.