Question

The radii of two charged metal spheres are 5 cm and 10 cm both having same charge 75 mC. If they are connected by a wire, the quantity of charge transferred through the wire is

• A. 25 mC
• B. 50 mC
• C. 75 mC
• D. Zero

Answer 1

The correct option is A 25 mC

$V=\frac{q_1+q_2}{C_1+C_2}=\frac{q_1+q_2}{4\pi {ϵ}_0[r_1+r_2]}=\frac{150\times {10}^{-3}\times 9\times {10}^9}{15\times {10}^{-2}}$
$V=9\times {10}^{9}V$
$q_1^1=C_{1}V=4\pi {ϵ}_0{r}_1\times 9\times {10}^9=\frac{1}{9\times {10}^9}\times 5\times {10}^{-2}\times 9\times {10}^9=5\times {10}^{-2}C$
$q_1^1=50mc$
$q_1-q_1^1=75-50=25mC$