Question

If $ 10^{10} $ electrons are acquired by a body every second, the time required for the body to get a total charge of $1 \,C$ will be

• A. 2h
• B. 2 days
• C. 2yr
• D. 20 yr

Answer 1

Answer: (D)

I electron has a charge of $1.6 \times 10^{-19} \,C \,10^{10}$
electrons would have a charge of $q =$ ne
$=1.6 \times 10^{-19} \times 10^{10}$
$=1.6 \times 10^{-9}\, C$
Thus, in $1 \,s$, charge accumulated $=1.6 \times 10^{-9} \,C$
So, time taken to accumulate $1\, C$
$=\frac{1}{1.6 \times 10^{-9}}=0.625 \times 10^{9}$
$=6.25 \times 10^{8} \,s=173611\, h$
$=7233$ days
$=20\, yr$