When a gold sheet is bombarded by a beam of `alpha`- particle , only a few of them get deflected whereas most go straight , undeflected . This is because:

Options

A. The force of attraction exerted on `alpha-` particles by electrons is insufficient
B. The volume of nucleus is much smaller than atom
C. The force of repulsion acting on fast moving `alpha-` particles due to nucleus is very small
D. The neutrons have no effect on `alpha-` particles

Explanation

To answer the question regarding why most alpha particles pass straight through a gold sheet while only a few get deflected, we can break down the explanation into a series of logical steps:

### Step-by-Step Solution:

1. **Understanding the Experiment**: The question refers to Rutherford's gold foil experiment, where a beam of alpha particles is directed at a thin sheet of gold.

2. **Nature of Alpha Particles**: Alpha particles are positively charged and relatively heavy compared to electrons. They are emitted from radioactive materials.

3. **Structure of the Atom**: According to the atomic model prior to Rutherford's experiment, atoms were thought to be a "plum pudding" structure, where electrons were embedded in a positively charged "soup."

4. **Observation of Deflection**: In the experiment, Rutherford observed that while most alpha particles passed straight through the gold foil, a small fraction were deflected at large angles.

5. **Conclusion about Atomic Structure**: Rutherford concluded that the atom is mostly empty space, with a small, dense, positively charged nucleus at its center. The nucleus contains most of the atom's mass.

6. **Reason for Deflection**: The deflection occurs only when an alpha particle comes very close to the nucleus. Since the nucleus is much smaller than the overall size of the atom, most alpha particles do not come close enough to be deflected.

7. **Final Conclusion**: Therefore, the reason that only a few alpha particles are deflected while most pass through undeflected is that the nucleus occupies a very small volume relative to the entire atom, allowing most particles to travel through the empty space without interaction.

### Summary of the Answer:
Most alpha particles go straight through the gold sheet because the nucleus is very small compared to the overall size of the atom, resulting in most of the alpha particles not coming close enough to be deflected.

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