Suppose that the strength of the electric field about an isolated point charge has a certain value at a distance of 1 m. How will the electric field strength compare at a distance of 2 m from the point charge? What law guides your answer?

Solution 31E Let the electric field strength be x. 2 Therefore, x = kq/1 ( q is the point charge) x = kq …..(1) When the distance is 2m, the field strength will be 2 x 1 kq/2 x 1 kq/4 x 1 x/4 (since x = kq ) Therefore, the electric field strength will be ¼ th when the distance is 2 m from the point charge. This law is known as the inverse square law.