Correct increasing order of penetrating powers of `alpha,beta` particles and `gamma`-rays, all moving with same kinetic energy is

Options

A. `alpha,beta,gamma`
B. `beta,alpha,gamma`
C. `gamma,beta,alpha`
D. All have same penetrating power as all have same kinetic energy

Answer

To determine the correct increasing order of penetrating powers of alpha particles, beta particles, and gamma rays, all moving with the same kinetic energy, we can analyze the properties of each type of radiation.

### Step-by-Step Solution:

1. **Understanding the Particles**:
- **Alpha particles** are composed of 2 protons and 2 neutrons (essentially helium nuclei). They are relatively heavy and carry a positive charge.
- **Beta particles** are high-energy, high-speed electrons or positrons. They are much lighter than alpha particles and carry a negative charge (in the case of electrons).
- **Gamma rays** are electromagnetic radiation and have no mass or charge. They travel at the speed of light.

2. **Penetrating Power**:
- The penetrating power of a particle refers to its ability to pass through materials. Generally, heavier particles (like alpha particles) are less penetrating than lighter particles (like beta particles) and electromagnetic radiation (like gamma rays).
- Alpha particles have low penetrating power due to their mass and charge; they can be stopped by a sheet of paper or even the outer layer of human skin.
- Beta particles have moderate penetrating power; they can penetrate paper but are stopped by materials like plastic or aluminum.
- Gamma rays have the highest penetrating power among the three; they can pass through most materials and require dense materials like lead or concrete for significant attenuation.

3. **Kinetic Energy Consideration**:
- Since the question specifies that all particles are moving with the same kinetic energy, we need to consider how this affects their velocities.
- For a given kinetic energy, heavier particles (like alpha particles) will have lower velocities compared to lighter particles (like beta particles). This means that even with the same kinetic energy, the alpha particles will not penetrate as effectively as beta particles.

4. **Conclusion**:
- Based on the properties and the kinetic energy consideration, we can conclude the order of penetrating powers:
- **Alpha particles** have the least penetrating power.
- **Beta particles** have moderate penetrating power.
- **Gamma rays** have the highest penetrating power.

Thus, the correct increasing order of penetrating powers is:
**Alpha particles < Beta particles < Gamma rays**

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