Question

A conductor carries a current of 0.2 A.In 30 s how many electrons will flow through the cross-section of the conductor, take $q=1.6\times {10}^{-19}C$ ?

• A. $0.375\times {10}^{19}$
• B. $375\times {10}^{19}$
• C. $3.75\times {10}^{19}$
• D. $37.5\times {10}^{19}$

Answer 1

The correct option is C $3.75\times {10}^{19}$

Given,

$I=0.2A$

$t=30sec$

$q=1.6\times {10}^{-19}C$

We know,

Charge= Current $\times$ Time

$Q=I\times t$

$\Rightarrow Q=0.2\times 30=6C$

Therefore, If $n$ electrons flow and $q$ is the charge on one electron, then total charged passed,

$Q=n\cdot q$

$\therefore n=\frac{Q}{q}=\frac{6}{1.6\times {10}^{-19}}=3.75\times {10}^{19}$

so, $3.75\times {10}^{19}$ electrons will flow through the cross section of the conductor.