The electric potential 1.34 m from a charge is 580 V. What is the value of the charge? Include the sign, + or - .

Answer 1

The formula for potential U caused by a charge Q at a point distance r from the charge is

U = kQ/r, where

k = 9×10⁹ Nm²C^-2 is Coulomb's constant.

Therefore

Q = Ur/k = 580×1.34/(9×10⁹) = 8.6×10^-8 C

The sign of the result is positive, which is consistent with the direction of electrical fields.

Positive charge causes an electrical field with lines pointing away from the charge.

That means that another positive charge placed in the field will have positive energy --

if going to infinity, the field will perform work.