Question

A current of 40mA flows for 0.4 hours through an electric circuit. Calculate the number of

electrons which will drift in the circuit.(Charge on 1 electron=1.6x10-19C)​

Answer 1

Answer:

3.6×10^15 electrons

Explanation:

hope you understand

Answer 2

Answer:

A current of 40mA flows for 0.4 hours through an electric circuit. The number of  electrons that will drift in the circuit will be $3.6\times 10^{20}$ electrons

Explanation:

• Consider a conductor of current flowing I, Q be the total charge of electrons and t be the time.

       Then, we have the expression for current as,

       $I=\frac{Q}{t}$  

      That is,

       $Q = It$            ...(1)

       Here Q is given by the expression,

       $Q = ne$  

       Or

       $n= \frac{Q}{e}$             ...(2)

       Where e is the charge of one electron and n is the number of electrons.

• In the question, it is given that,

       $t = 0.4h= 0.4\times 60\times 60 s= 1440s$

      $I = 40mA = 40\times 10^{-3} A$  

       $e = 1.6\times 10^{-19}C$

      Substitute these values into equation (1)

      $Q = (40\times 10^{-3}\times 1440 )= 57.6 C$

      Then equation(2) becomes,

      $n= \frac{57.6}{1.6\times 10^-19}= 3.6\times 10^{20}$ electrons