Question

A student measures a constant current of 0.87 A passing through a copper wire.
The number of electrons that passes through a cross section in this wire each minute is approximately:

• A. $3.3\times {10}^{20}electrons$
• B. $5.4\times {10}^{18}electrons$
• C. $8.4\times {10}^{-18}electrons$
• D. $1.4\times {10}^{-19}electrons$

Answer 1

The correct option is A $3.3\times {10}^{20}electrons$

Given : $I=0.87$ A $t=1$ minute $=60$ seconds

Thus Amount of charge passing per minute $Q=It=0.87\times 60=52.2$ C

$\therefore$ Number of electrons passing each minute $n=\frac{52.2}{1.6\times {10}^{-19}}\approx 3.31\times {10}^{18}$ electrons