Question

If the electronic charge is $1.6\times {10}^{-19}$C, then the number of electrons passing through a section of wire per second, when the wire carries a current of $2$ ampere is?

• A. $1.25\times {10}^{17}$
• B. $1.6\times {10}^{17}$
• C. $1.25\times {10}^{19}$
• D. $1.6\times {10}^{19}$

Answer 1

The correct option is C $1.25\times {10}^{19}$

Current is the amount of charge passing through a conductor in a particular interval of time. So according to the definition,the formula for the current is:

$I=\frac{q}{tI}=2A$ and

$t=1$sec Therefore,

$Q=I\times tQ=2\times 1=2C$

One electon consists of a charge of $1.6\times {10}^{-19}C$

Then the number of electrons passing would be:

$Q=n\times en=\frac{q}{en}$

$=2/(1.6\times {10}^{-19})$

$=1.25\times {10}^{19}electrons$