An `alpha`-particle of velocity `2.3xx10^7` m/s exhibits back scattering by a gold foil (Z=79).Predict the maximum possible radius of the gold nucleus approximately Charge of mass ratio for `alpha`-particle is `4.8xx10^7` C/kg.

Explanation

To solve the problem of predicting the maximum possible radius of the gold nucleus when an alpha particle exhibits back scattering, we can follow these steps:

### Step 1: Understand the Concept of Closest Approach
The maximum possible radius of the gold nucleus can be approximated by the distance of closest approach (R₀) of the alpha particle to the nucleus. At this distance, the kinetic energy of the alpha particle is equal to the electrostatic potential energy between the alpha particle and the gold nucleus.

### Step 2: Write Down the Energy Equations
The kinetic energy (KE) of the alpha particle can be expressed as:
\[ KE = \frac{1}{2} mv^2 \]
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