Question

Faraday conducted many experiments. So naturally he would have to make several calculations.
He once passed a current of 1 A through a wire. What do you think is the number of electrons that moved past a point in the wire in one second?

• A. $6.023\times {10}^{23}$
• B. $3.12\times {10}^{18}$
• C. $3.02\times {10}^{23}$
• D. $6.23\times {10}^{18}$

Answer 1

The correct option is D $6.23\times {10}^{18}$

Let's break this down.

He passed a current of 1 A in 1 sec through the wire. So, what would be the charge passing in one second?
$Q=I\times t=1A\times 1sec=1C$

So, a charge of 1 C is passing in 1 second.

Now, how many electrons does a 1 C charge contain?

We can find this in 2 ways.

$1Faraday=96500C=6.023\times {10}^{23}electrons\Rightarrow 1C=\frac{6.023\times {10}^{23}}{96500}=6.23\times {10}^{18}electrons$

Or you could use the charge of 1 electron = $1.6\times {10}^{-19}C$
$\Rightarrow 1C=\frac{1}{1.6\times {10}^{-19}}\Rightarrow 1C=6.23\times {10}^{18}electrons$

You will need to keep the value of 1 F or the charge of one electron in mind!