Question

Two charges of equal amount +Q are placed on a line. Another charge q is placed at the mid-point of the line. The system will be in equilibrium if the value of q is

• A. $\frac{Q}{4}$
• B. $-\frac{Q}{2}$
• C. $+\frac{Q}{2}$
• D. $+\frac{Q}{4}$

Answer 1

Answer: (A)

$\frac{Q}{4}$

Answer 2

For the equilibrium of the system
Force on +Q charge,$\frac{KQ^{2}}{\ell^{2}} =\frac{KQq}{\ell^{2}} \times4$
$q=\frac{-Q}{4}$