# How do I find the electric potential and field strength between two point charges?

If you had two point charges, and directly inbetween them you were asked to find a) the resultant electric potential and b) the resultant electric field strength, would you for a) find the electric potential caused by either point charge and then find the sum, and for b) find the electric field strength caused by either point charge and then find the difference?
Original post by maybemiro
If you had two point charges, and directly inbetween them you were asked to find a) the resultant electric potential and b) the resultant electric field strength, would you for a) find the electric potential caused by either point charge and then find the sum, and for b) find the electric field strength caused by either point charge and then find the difference?

The key ideas are electric potential at a point is the scalar sum of the electric potential due to the charges while the electric field strength at a point is the vector sum of the electric field strength due to the charges.

If the two-point charges are similar, then the electric potential at a point between them is computed by adding the electric potential due q1 and q2 respectively.
As for electric field strength, you need to subtract electric field strength due to q1 from electric field strength due to q2 or vice versa.

If the two-point charges are different (one is positive and the other is negative), then the electric potential at a point between them is also computed by adding the electric potential due q1 and q2 respectively but with the sign.

As for electric field strength, you need to add the electric field strength due to q1 and q2 respectively.