Assuming that the charges of an electron is $1.6 \times 10^{18}$ coulombs, the number of electrons passing through a section of wire per sec, when the wire carries a current of one ampere is :
✓
$0.625 \times 10^{19}$
B
$1.6 \times 10^{19}$
C
$1.6 \times 10^{19}$
D
$0.627 \times 10^{17}$
Answer
Correct option: A.
$0.625 \times 10^{19}$
(A) $0.625 \times 10^{19}$ Explanation : Charge $=q=e=1.6 \times 10^{-19} C$ Number of electrons $=n=$ ? Electric current $= I =1 A$ Time $=t=1 S$ $ \begin{aligned} I & =\frac{q}{t}=\frac{n e}{t} \\ I & =\frac{1.6 \times 10^{-19} \times n}{1} \\ \Rightarrow n & =\frac{1}{1.6 \times 10^{-19}}=0.625 \times 10^{19} \end{aligned} $