Question

Calculate the flow of current when $2.4 \times {10^{20}}$ electrons flow through the circuit in 10 hours.

Answer 1

Hint: Current is the flow of electrons. It is determined by the number of electrons times charge on one electron passing through the circuit per second.

Complete step by step answer:
The flow of electrons in a circuit is called electric current. It is the rate at which charge flows. The direction of current is taken in the direction in which positive charge moves. Its SI unit is ampere A. Electron flow is what we simply mean by current. Here we are given the number of electrons flowing through the circuit. We need to find the charge q which is determined by charge on one electron times the number of electrons. Current is charge q flowing through time t.
We are given.
Number of electrons $N = 2.4 \times {10^{20}}$
Time $t = 10hours$
We know e is the charge on one electron $e = 1.6 \times {10^{ - 19}}C$
Current is given by charge q flowing through circuit in one second and is given by \[i = \dfrac{q}{t}\]
Charge q is the total number of electrons times charge on one electron in coulomb..
\[
  q = Ne \\
\Rightarrow q = 2.4 \times {10^{20}} \times 1.6 \times {10^{ - 19}}C \\
\Rightarrow q = 3.84 \times {10^1}C \\
 \]
Time is given to us in hours but in SI units of time is seconds. So we will be converting hours to seconds.
$
  t = 10hours \\
\Rightarrow t = 10 \times 60 \times 60\sec \\
\Rightarrow t = 36000\sec \\
 $
Putting the values of q and t in the formula
\[
  i = \dfrac{q}{t} \\
\Rightarrow i = \dfrac{{3.84 \times {{10}^1}}}{{36000}}A \\
\Rightarrow i = 1.066 \times {10^{ - 3}}A \\
 \].

Note:Electron flow is what we meant by electric current. The formula that we used while solving is what we understand by the definition of electric current. Rate of flow of electron charge is called current. Current is total charge flowing through circuit per second.