Which of the following projectiles is the best for bombarding the nuclide?

Options

A. `alpha`-particle
B. Proton
C. Deuteron
D. Neutron

Explanation

To determine which projectile is best for bombarding a nuclide, we need to analyze the properties of various projectiles typically used in nuclear reactions. Here’s a step-by-step solution:

### Step 1: Understand the Types of Projectiles
Common projectiles used in nuclear reactions include:
- Neutrons
- Protons
- Alpha particles
- Gamma rays

### Step 2: Analyze the Properties of Neutrons
Neutrons are unique among these projectiles due to the following properties:
- **Electrically Neutral**: Neutrons do not carry a charge, which means they are not repelled by the positively charged nucleus of the target nuclide. This allows them to penetrate the nucleus more effectively.
- **High Penetration Ability**: Because they are neutral, neutrons can easily enter the nucleus without being deflected by the electric field, making them highly effective for nuclear reactions.
- **Thermal Neutrons**: Neutrons can be slowed down (thermalized) by interactions with materials, which makes them more effective at lower energies for certain reactions.

### Step 3: Compare with Other Projectiles
- **Protons**: Positively charged and are repelled by the nucleus, requiring higher energy to overcome this repulsion.
- **Alpha Particles**: Heavily charged and relatively large, making them less effective for penetrating the nucleus compared to neutrons.
- **Gamma Rays**: High-energy electromagnetic radiation, but they do not interact strongly with the nucleus for nuclear reactions.

### Step 4: Conclusion
Given the properties of neutrons, they are the best projectiles for bombarding nuclides. Their lack of charge allows them to penetrate the nucleus effectively, and they can be used in various nuclear reactions without the need for high kinetic energy.

### Final Answer
The best projectile for bombarding the nuclide is **neutron**.

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