Find the electric potential at the axis of a uniformly charged disc and use potential to find the electric field at same point.

Explanation

To find the electric potential at the axis of a uniformly charged disc and then use that potential to find the electric field at the same point, we can follow these steps:

### Step 1: Define the Problem
We have a uniformly charged disc with surface charge density \( \sigma \). We want to find the electric potential \( V \) at a point \( P \) located along the axis of the disc at a distance \( x \) from its center.

### Step 2: Consider a Differential Element
Consider a small ring of radius \( r \) and thickness \( dr \) on the disc. The area of this ring is given by:
\[
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