Which of the following pairs particles cannot exert nuclear force on each other ?

Options

A. proton and electron
B. Neutron and electron
C. Electron and neutron
D. All of these

Answer

To determine which pairs of particles cannot exert nuclear force on each other, we first need to understand the nature of nuclear forces and the particles involved.

### Step-by-Step Solution:

1. **Understanding Nuclear Forces**:
- Nuclear forces are short-range forces that act between nucleons (protons and neutrons) within the nucleus of an atom. These forces are responsible for holding the nucleus together.

2. **Identifying the Particles**:
- The main particles involved in nuclear forces are protons and neutrons, which are both found in the nucleus. Electrons, on the other hand, are not part of the nucleus; they orbit around it.

3. **Analyzing the Pairs**:
- **Protons and Neutrons**: These particles can exert nuclear force on each other because they are both located in the nucleus.
- **Protons and Electrons**: Protons are in the nucleus, while electrons are in orbits. They do not exert nuclear force on each other; instead, they experience electrostatic forces due to their opposite charges.
- **Neutrons and Electrons**: Similar to protons, neutrons are in the nucleus, and electrons are in orbits. They also do not exert nuclear force on each other.
- **Neutrons and Neutrons**: Neutrons can exert nuclear force on each other as they are both in the nucleus.

4. **Conclusion**:
- The pairs that cannot exert nuclear force on each other are:
- Protons and Electrons
- Neutrons and Electrons

5. **Final Answer**:
- Therefore, the correct answer is that the pairs of particles that cannot exert nuclear force on each other are **Protons and Electrons, and Neutrons and Electrons**.