Question

Two objects P and Q carry charges $-3.00\mu C$ and $-0.44\mu C$. What is the number of electrons transferred from P to Q, so that they acquire equal charges?

• A. $8\times {10}^{13}$
• B. $8\times {10}^{12}$
• C. $8\times {10}^{14}$
• D. $8\times {10}^{-13}$

Answer 1

The correct option is B $8\times {10}^{12}$

Let final charge on each of P and Q be $Q$.

$Q+Q=-3-0.44=-3.44\mu C$

$⟹Q=-1.72\mu C$

Hence, charge transferred$=q=3-1.72=1.28\mu C$

Charge on each electron$=e=1.6\times {10}^{-19}C$

Hence, number of electrons transferred$=N=\frac{q}{e}$

$⟹N=\frac{1.28\times {10}^{-6}}{1.6\times {10}^{-19}}$

$⟹N=8\times {10}^{12}$