In the nucleus of helium if `F_1 is the net force between two protons, `F_2` is the net force between two neutrons and `F_3` is the net force between a proton and a neutron. Then,

Options

A. (a) `F_1=F_2=F_3`
B. (b) `F_1gtF_2gtF_3`
C. (c) `F_2gtF_3gtF_1`
D. (d) `F_2=F_3gtF_1`

Answer

To solve the problem, we need to analyze the forces acting between the particles in the helium nucleus, which consists of two protons and two neutrons.

1. **Understanding the Forces**:
- **F1** is the net force between the two protons.
- **F2** is the net force between the two neutrons.
- **F3** is the net force between a proton and a neutron.

2. **Nature of Nuclear Forces**:
- The nuclear force is a strong interaction that acts between nucleons (protons and neutrons) in the nucleus.
- It is important to note that these forces are short-range and are generally considered to be attractive.

3. **Comparing the Forces**:
- The strong nuclear force is similar for all nucleon pairs (proton-proton, neutron-neutron, and proton-neutron).
- Therefore, we can conclude that the magnitudes of these forces are approximately equal due to the nature of the strong nuclear force being independent of the type of nucleon pair.

4. **Conclusion**:
- Since the nuclear forces are the same for all nucleon pairs in the helium nucleus, we can state that:
\[ F_1 = F_2 = F_3 \]

### Final Answer:
Thus, in the nucleus of helium, we have:
\[ F_1 = F_2 = F_3 \]