Compared with other common forms of radiation, alpha particles have what relative mass?

Compared with other common forms of radiation, alpha particles have what relative mass?

• A. They have the greatest mass.
• B. They have the least mass.
• C. They have the same mass as beta particles.
• D. Their mass is negligible.

Answer: (A)

The mass of different radiation types varies a lot. An alpha particle is a helium nucleus, made of two protons and two neutrons, giving it about 4 atomic mass units. A beta particle is an electron, with a mass about 9.11 x 10^-31 kg (roughly 1/1836 of a proton’s mass). Gamma rays are photons and have no rest mass. Because of these masses, alpha particles are far heavier than beta particles and gamma rays. So, among these common forms, alpha particles have the greatest mass.

The mass of different radiation types varies a lot. An alpha particle is a helium nucleus, made of two protons and two neutrons, giving it about 4 atomic mass units. A beta particle is an electron, with a mass about 9.11 x 10^-31 kg (roughly 1/1836 of a proton’s mass). Gamma rays are photons and have no rest mass. Because of these masses, alpha particles are far heavier than beta particles and gamma rays. So, among these common forms, alpha particles have the greatest mass.