Question

What will be the potential if atest charge id placed 2.08x10^-3 m away from the +5.02x10-13C source charge?

Answer 1

The test potential will be

$$V=\frac{kq}{r}=\frac{9·10^9·5.02·10^{-13}}{2.08·10^{-3}}=2.17\text{ V}.$$