Question

$A$ and $B$ are two hollow metal spheres of radii $50cm$ and $1m$ carrying charges $0.6\mu C$ and $1\mu C$ respectively. They are connected externally by a conducting wire. Now the charge flows from :

• A. $A$ to $B$ till the charges become equal
• B. $A$ to $B$ till the potentials become equal
• C. $B$ to $A$ till the charges become equal
• D. $B$ to $A$ till the potentials become equal

Answer 1

Answer: (B)

$A$ to $B$ till the potentials become equal

The potential of a sphere of radius $r$ carrying a charge $q$ is $\frac{kq}{r}$.

Hence potential of first sphere=$V_A=\frac{k\left(0.6\mu C\right)}{0.5m}$

Potential of second sphere=$V_B=\frac{k\left(1\mu C\right)}{1m}$

$⟹V_A>V_B$

Hence charge flows from A to B till the potentials become equal.