Question

A metal detector has a current of 60mA What is the number of free electron that flow across a cross section of the conductor in 40second?

Answer 1

1 * 10^19 (apprx)

Answer 2

Current= \(60mA\) or \(60\times 10^{-3}A\)
We know current is charge divided by time ( in seconds) so
\[60 \times 10^{-3}= \frac{Q}{40}\]
So
\[Q=40 \times 60 \times 10^{-3}=2.4 Coulombs\]
Now no. of electrons flowing= total charge/(charge of an electron)
\[\text{No. of electrons}=\frac{2.4}{1.6 \times 10^{-19}}\]
I think you can solve now

Answer 3

Thanks~ solved