What is the Difference Between Alpha and Beta Particles?

🆚 Go to Comparative Table 🆚

Alpha and beta particles are two types of radiation emitted by unstable atomic nuclei during radioactive decay. They have different properties and effects on living tissue:

Alpha particles:

  • Composed of two neutrons and two protons, essentially a helium nucleus.
  • Carry a positive charge.
  • Large in size compared to beta particles.
  • Have low penetration power, stopped by a thick sheet of paper or the outer layer of dead skin.
  • Most dangerous when inhaled or ingested, as they can damage sensitive living tissue.

Beta particles:

  • Consist of high-energy electrons or positrons with a negative charge.
  • Much smaller in size than alpha particles.
  • Have higher penetration power, capable of penetrating the skin and causing damage such as skin burns.
  • Can be stopped by a layer of clothing or a thin layer of a substance like aluminum.
  • Less damaging to living tissue and DNA compared to alpha particles due to more widely spaced ionizations.

In summary, alpha particles are larger and carry a positive charge, while beta particles are smaller and carry a negative charge. Alpha particles have lower penetration power but can cause more damage to living tissue when ingested or inhaled. Beta particles have higher penetration power but are less damaging to living tissue and DNA.

Comparative Table: Alpha vs Beta Particles

Here is a table summarizing the differences between alpha and beta particles:

Property Alpha Particles Beta Particles
Composition Helium nuclei (2 protons and 2 neutrons) Fast-moving electrons or positrons (high-energy neutrinos)
Size Large (8000 times heavier than beta particles) Much smaller than alpha particles
Mass Positive charge Negative charge or no charge
Penetration Power Low (can be stopped by a thick sheet of paper) Higher than alpha particles (can travel further in air)
Energy Less energy (lose energy over short distances) More energy
Emission Source Heavy radioactive elements like uranium, radium, thorium, and polonium Unstable atoms with too many neutrons like hydrogen-3 (tritium), carbon-14, and strontium-90
Radioactive Decay Alpha decay Beta decay

Please note that a positron is an anti-particle with a positive charge. Microscopic black holes and fast-moving neutrinos can also emit beta particles.