Question

Two charges q and Q are separated by a distance R. If both charges are doubled to 2q and 2Q but the distance R remains the same, the new electric force is _____ the old force.

  

 

Answer 1

Explanations & Calculations

• Just apply the formula of Coulomb's law to both occasions and do the necessary arrangements.

$\qquad\qquad \begin{aligned} \small F&=\small k\frac{Q.q}{R^2}\qquad\cdots\,\cdots(1)\\ \\ \small F_1&=\small k\frac{(2Q).(2q)}{R^2}\\ &=\small 4\Big[k\frac{Q.q}{R^2}\Big]\\ &=\small 4.F \end{aligned}$

• The new electric force is 4 times the old force.