Which is most ionising

Options

A. X-rays
B. `gamma`-rays
C. `beta-`rays
D. `alpha`-rays

Answer

To determine which type of radiation is the most ionizing among the given options (X-rays, gamma rays, beta rays, and alpha rays), we can follow these steps:

### Step-by-Step Solution:

1. **Understand Ionization**: Ionization occurs when high-energy radiation strikes an atom, causing it to lose an electron and become an ion. The ability of radiation to ionize atoms depends on its energy and mass.

2. **Identify the Types of Rays**:
- **Alpha Rays**: Composed of 2 protons and 2 neutrons (helium nucleus). They have a relatively large mass and charge.
- **Beta Rays**: High-energy electrons that are lighter than alpha particles and have a negative charge.
- **Gamma Rays**: High-energy electromagnetic radiation with no mass or charge.
- **X-rays**: Similar to gamma rays but typically have lower energy.

3. **Compare Ionizing Capacities**:
- **Alpha Rays**: Due to their large mass and charge, alpha particles have a high ionizing capacity but low penetration ability. They can ionize atoms effectively over a short distance.
- **Beta Rays**: These are less ionizing than alpha rays because they are lighter and have less charge.
- **Gamma Rays**: These have the least ionizing capacity because they are neutral and have no mass, allowing them to pass through matter without causing ionization.
- **X-rays**: Similar to gamma rays but generally less ionizing than alpha rays.

4. **Conclusion**: Based on the comparison, alpha rays are the most ionizing radiation among the options provided.

### Final Answer:
The correct option is **alpha rays**.

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