(a) Obtain the expression for the potential due to a point charge.
(b) Use the above expression to show that the potential, due to an electric dipole (length 2a), varies as the inverse square' of the distance r of the 'field point' from the centre of the dipole for `rgta`.

Explanation

### Solution

#### (a) Expression for the Potential Due to a Point Charge

1. **Definition of Electric Potential**:
The electric potential \( V \) at a point in space due to a point charge \( Q \) is defined as the work done in bringing a unit positive charge from infinity to that point.

2. **Work Done Calculation**:
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