Question

Two small identical conducting balls $A$ and $B$ of charges $+10\mu \text{C}$ and $+30\mu \text{C}$ respectively are kept at a separation of $50\text{cm}$. These balls have been connected by a wire for a short time.

$\left(\text{i}\right)$ The final charge on each of the balls $A$ and $B$ will be

​​​​​​​$[$1 Mark$]$

• A. $10\mu \text{C}$ and $30\mu \text{C}$ respectively
• B. $20\mu \text{C}$ on each ball
• C. $30\mu \text{C}$ and $10\mu \text{C}$ respectively
• D. $-40\mu \text{C}$ and $80\mu \text{C}$ respectively

Answer 1

The correct option is B $20\mu \text{C}$ on each ball


When the balls are connected by a wire, redistribution of charges takes place such that charges on each ball will be equal (only if the balls are identical) and
charge on each ball
$Q=\frac{\text{total charge before connection}}{2}$
$\Rightarrow Q=\frac{10\mu \text{C}+30\mu \text{C}}{2}=+20\mu c$
$\therefore$ option $\left(b\right)$ is correct