Question

Although$\mathbf{\gamma }$ rays are far more penetrating than particles, the latter are more likely to cause damage to an organism. Why? Which type of radiation is more effective at promoting the ionization of biomolecules?

Short answer

The alpha particles possess the greatest ionizing power and the lowest penetrating power. Alpha particles promote the ionization of biomolecules.

Step-by-step solution

Types of radiation.

The three main types of radiation are:

• Alpha particles- Less penetrating, strongly ionizing
• Beta particles- Moderately penetrating, moderately ionizing
• Gamma rays- More penetrating, weakly ionizing

Explanation of rays that causes damage to an organism.

As we know, the bigger the mass present, the greater the ionizing power and the lower the penetrating power.

Since gamma rays have no mass, they have the greatest penetration power (they can readily enter, pass through, and exit the human body), but they have low ionizing power.

However, because the alpha particle has the greatest mass (when compared to beta and gamma rays), it has the greatest ionizing power and the lowest penetrating power (which can be stopped by dead skin on the human body).

When alpha particles are outside of a human body, they are harmless; nevertheless, when breathed or swallowed, alpha particles are unable to escape the human body (due to their low penetrating power and strong ionizing power) and can cause substantial biological damage.