Are alpha or beta particles smaller?

Are alpha or beta particles smaller?

• A. Beta particles
• B. Alpha particles
• C. Gamma rays
• D. X-rays

Answer: (A)

Beta particles are smaller than alpha particles. An alpha particle is a helium nucleus, consisting of two protons and two neutrons, so it has a relatively large mass and bulky size. A beta particle is an electron (or positron), which is far lighter. That big difference in mass and size means beta particles are the smaller of the two. (Gamma rays and X-rays are photons, not massive particles, so they don’t have a size in the same sense.)

Beta particles are smaller than alpha particles. An alpha particle is a helium nucleus, consisting of two protons and two neutrons, so it has a relatively large mass and bulky size. A beta particle is an electron (or positron), which is far lighter. That big difference in mass and size means beta particles are the smaller of the two. (Gamma rays and X-rays are photons, not massive particles, so they don’t have a size in the same sense.)