Alpha rays are positively charged particles. Alpha-particle is a highly active and energetic helium atom that contains two neutrons and protons. These particles have the minimum penetration power and highest ionization power. They can cause serious damage if get into the body due to their high ionization power. Alpha particles are relatively slow and heavy compared with other forms of nuclear radiation
- The kinetic energy of the alpha particles is 5 MeV.
- The photographic plates are affected by the alpha particles.