Question

Two positive charges of magnitude 2.4 x 10-9 C and 1.6 x 10-9 C are separated in air by a distance of 2cm. how much electrostatic potential is produced by the two charges at midway between them? 

Answer 1

Find the potential from each charge at the midway:

$$V_1=\frac{kq_1}{r}=2157\text{ V}.\\\space\\ V_2=\frac{kq_2}{r}=1438\text{ V}.\\\space\\ V=V_1+V_2=3595\text{ V}.$$