Answer:
F = K Q1 * Q2 / R^2 force between 2 charged particles
F2 / F1 = R1^2 / R2^2 = (R1 / R2)^2 = (R1 / R1 /2)^2 = 2^2 = 4
d) the force would be increased by a factor of 4
check the image above please
