Question

A current of $1\cdot 6mA$ flows through a conductor. If charge on an electron is $-1.6\times {10}^{-19}$ coulomb, find the number of electrons that will pass each second through the cross section of that conductor.

• A. ${10}^5$
• B. ${10}^4$
• C. ${10}^{16}$
• D. ${10}^9$

Answer 1

The correct option is C ${10}^{16}$

A current of $1$ ampere is said to flow when $1$ coulomb of charge passes a given point in $1$ sec.
Charge flowing through a conductor in one second is given as $charge=current\times time$. It is given that the current through the conductor is $1.6mA$, that is, $1.6\times {10}^{-3}A$
Therefore, charge =$1.6\times {10}^{-3}\times 1=1.6\times {10}^{-3}C$.
Number of electrons passing through the conductor in one second is given as $\frac{Q}{e}=\frac{1.6\times {10}^{-3}}{1.6\times {10}^{-19}}={10}^{16}$
Hence, the number of electrons passing through the conductor in 1 second is ${10}^{16}$