Question

Point P and point charge Q are separated by a distance R. The electric field at point P has magnitude E. How could the magnitude of the electric field at point P be doubled to 2E?,

Answer 1

We know , E = kQ/r^2 where q = charge and r is separation between point and point charge. Now, At P, E= kQ/r^2 Since, Q can't be changed, we can do that by varying r 2E = 2kq/r^2 2E = kq/ (r/ sqrt2)^2 Hence, if we bring Q closer such that distance between P and Q becomes r/ sqrt 2, E will get doubled.