Question

A conducting sphere of radius $R$ having charge $q$ is joined to another conducting sphere of radius $2R$ having charge $-2q$. The charge flowing between them will be

• A. $q$
• B. $\frac{2q}{3}$
• C. $\frac{q}{3}$
• D. $\frac{4q}{3}$

Answer 1

The correct option is D $\frac{4q}{3}$

Initial charge on sphere of radius $R=q$
Charge on this sphere after joining
$q^{\prime }=\frac{\{q+(-2q\left)\right\}R}{R+2R}=\frac{-q\times R}{3R}=\frac{-q}{3}$
$\therefore$ Charge flowing between them
$q-(-\frac{q}{3})=q+\frac{q}{3}=\frac{4q}{3}$.