Arrange the `alpha`, `beta` and `gamma` radiation in ascending order of their biological damage. Give reason.

Answer

To arrange alpha, beta, and gamma radiation in ascending order of their biological damage, we need to consider their properties and how they interact with matter, particularly biological tissues.

### Step-by-Step Solution:

1. **Understanding the Types of Radiation**:
- **Alpha Radiation**: Consists of alpha particles, which are helium nuclei (2 protons and 2 neutrons). They carry a positive charge (+2e).
- **Beta Radiation**: Consists of beta particles, which are high-energy, high-speed electrons or positrons. They carry a negative charge (-e for electrons).
- **Gamma Radiation**: Consists of gamma rays, which are high-energy electromagnetic radiation. They have no charge.

2. **Penetrating Power**:
- **Alpha Particles**: Due to their larger mass and positive charge, alpha particles have low penetrating power. They can be stopped by a sheet of paper or even the outer layer of human skin.
- **Beta Particles**: Beta particles have a greater penetrating power than alpha particles but can be stopped by a few millimeters of plastic or glass.
- **Gamma Rays**: Gamma rays have the highest penetrating power and can pass through most materials, including human tissue. They require dense materials like lead or several centimeters of concrete for shielding.

3. **Biological Damage**:
- Biological damage is related to the energy deposited in biological tissues. Since alpha particles have low penetrating power, they cause significant damage if they interact with tissues (e.g., if ingested or inhaled) but are less damaging externally.
- Beta particles can penetrate deeper into tissues than alpha particles, leading to more biological damage.
- Gamma rays, while less ionizing than alpha and beta particles, can penetrate deeply and affect internal organs, leading to significant biological damage.

4. **Arranging in Ascending Order of Biological Damage**:
- Based on the penetrating power and the nature of their interactions with biological tissues, we can arrange the types of radiation in ascending order of biological damage:
- **Alpha Radiation** (least damage)
- **Beta Radiation**
- **Gamma Radiation** (most damage)

### Final Order:
**Alpha < Beta < Gamma**

### Reason:
The order is determined by the penetrating power of the radiation. Alpha particles have the least penetrating power and therefore cause the least biological damage when outside the body. Beta particles cause more damage due to their greater penetration, and gamma rays, despite being less ionizing, cause the most damage due to their ability to penetrate deeply into tissues.