Two metal spheres of radii $1\ cm$ and $3\ cm$ carry charges $-1 imes…

Question

Two metal spheres of radii $1\ cm$ and $3\ cm$ carry charges $-1	imes10^{-2}\ C$ and $+5	imes10^{-2}\ C$. When joined by a thin wire, the final charge on the bigger sphere is

Accepted Answer

D. $3	imes10^{-2}\ C$

1. Joined conductors reach the same potential, so charge distributes in proportion to radius: $q \propto r$.
2. Total charge $= -1	imes10^{-2} + 5	imes10^{-2} = 4	imes10^{-2}$ C, shared in ratio $1:3$.
3. Bigger sphere gets $\dfrac{3}{4}	imes4	imes10^{-2} = 3	imes10^{-2}$ C.
_Source: Samacheer Kalvi Class 12 Physics Vol.1, Unit 1 'Electrostatics', Evaluation Q.15 (AIPMT-2012)_

Answer

$4	imes10^{-2}\ C$

Answer

$1	imes10^{-2}\ C$

Answer

$2	imes10^{-2}\ C$

Two metal spheres of radii $1\ cm$ and $3\ cm$ carry charges $-1\times10^{-2}\ C$ and $+5\times10^{-2}\ C$. When joined by a thin wire, the final charge on the bigger sphere is