# Potential with an edge

**Electricity and Magnetism**Level 3

A thin disc of radius \(\displaystyle R = 10 \text{ cm } \)made of non-conducting material is charged uniformly so as to acquire a uniform surface charge density \(\displaystyle \sigma = 5 \text{ nC}/\text{m}^2 \).

Find the potential at the edge of the disc in **Volts**.

**Details and Assumptions**

- \(\displaystyle \frac{1}{4 \pi \epsilon _{0} } = 9 \times 10^{9} \text{ N}\cdot \text{m}^2 / \text{C}^2 \)