What are the magnitude and direction of the electric field at a point midway between a -7.0 µC and a +6.0 µC charge 2.5 cm apart? Assume no other charges are nearby.

Answer 1

At the midway point, the distance is r = 0.0125 m from each charge.

The fields due to each charge are in the same direction at points in between.

Coulomb's law tells you that the E-field due to a charge q is

E = k q/r^2

Add the fields of each charge. You may need to look up the Coulomb constan,t k.

Answer 2

a) What is the magnitude of the electric field at a point midway between a −8.5μC and a +8.5μC charge 8.0cm apart? Assume no other charges are nearby.
b) What is the direction of the electric field?