An isolated point charged point particle produces an electric field with magnitude E at a point 2 m away from the charge.A point at which the field magnitude is E/4 is:
A)0.5 m away from the charge
B)1 m away from the charge
C)2 m away from the charge
D)4 m away from the charge
E)8 m away from the charge

Question

Quizplus · Accepted Answer

The electric field (E) due to a point charge decreases with the square of the distance (r) from the charge, according to Coulomb's law, $E \propto \frac{1}{r^2}$. If the field magnitude is $E$ at a distance of 2 m, to have a field magnitude of $E/4$, the distance must be doubled, because $E/4 = E \times (\frac{1}{2})^2$, which means the distance is 4 m away from the charge.

An Isolated Point Charged Point Particle Produces an Electric Field