In the geiger -marsden scattering experiment, in case of head- on collision the impact parameter should be

Options

A. maximum
B. minimum
C. infinite
D. zero

Explanation

To solve the question regarding the impact parameter in the Geiger-Marsden scattering experiment during a head-on collision, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Impact Parameter**:
The impact parameter (b) is defined as the perpendicular distance from the center of the target nucleus to the initial trajectory of the incoming particle (in this case, an alpha particle).

2. **Head-On Collision Definition**:
A head-on collision occurs when the incoming particle directly strikes the center of the nucleus. In this scenario, the impact parameter is zero because the path of the incoming particle is aligned with the center of the nucleus.

3. **Mathematical Representation**:
For a head-on collision, we can express the impact parameter mathematically as:
\[ b = 0 \]
This indicates that the alpha particle is directly hitting the nucleus without any offset.

4. **Conclusion**:
Therefore, in the case of a head-on collision in the Geiger-Marsden scattering experiment, the impact parameter should be zero.

### Final Answer:
The impact parameter in case of a head-on collision should be **0**.

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