Question

Two bodies X and Y carry charges $-6.6\mu C$ and $-5\mu C$.How many electrons should be transferred from X and Yso that they acquire equal charges?

• A. $2\times {10}^{12}$
• B. $5\times {10}^{14}$
• C. $5\times {10}^{12}$
• D. $5\times {10}^{13}$

Answer 1

The correct option is C $5\times {10}^{12}$

Two bodies X and Y carry charges $-6.6\times {10}^{-6}C$ and $-5\times {10}^{-6}C$ respectively.

$\Rightarrow$ X has excess charge of $-1.6\times {10}^{-6}C$ composed to Y.

$\Rightarrow$ X has to give a charge $-0.8\times {10}^{-6}C$ if charge on both have to be same.

The charge on one electron is $-1.6\times {10}^{-19}C$

$\Rightarrow$ Number of electrons required to transfer a charge of $-0.8\times {10}^{-6}C$

$=\frac{-0.8\times {10}^{-6}}{-1.6\times {10}^{-19}}=5\times {10}^{12}$