For scattering by an inverse square field (such as that produced by a charged nucleus in Rutherford's model), the relation between impact parameter b and the scattering angle `theta` is given by,
`b=(Ze^(2)cot theta//2)/(4pi epsilon_(0)((1)/(2)mv^(2)))`
What is the impact parameter at which the scattering angle is `90^(@)` for Z = 79 and initial energy equal to 10MeV ?

Explanation

To find the impact parameter \( b \) at which the scattering angle \( \theta \) is \( 90^\circ \) for \( Z = 79 \) and an initial energy of \( 10 \, \text{MeV} \), we will follow these steps:

### Step 1: Write down the formula for impact parameter
The relation between the impact parameter \( b \) and the scattering angle \( \theta \) is given by:
\[ b = \frac{Z e^2 \cot(\theta/2)}{4 \pi \epsilon_0 \left(\frac{1}{2} mv^2\right)} \]

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