Q. A conducting sphere of radius $R,$ and carrying a charge $q$ is joined to a conducting sphere of radius $2R,$ and carrying a charge $- 2q.$ The charge flowing between them will be
A) $\frac{q}{3}$
B) $\frac{2q}{3}$
C) $q$
D) $\frac{4q}{3}$
Explanation
(d) Initial charge on sphere of radius $R = q$
Charge on this sphere after joining
$q^{'} = \frac{(q + ( - 2q) \times R}{R + 2R} = \frac{- q \times R}{3R} = - \frac{q}{3}$
Now charge flowing between them $= q - \left( - \frac{q}{3} \right) = \frac{4q}{3}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.