Question

What is meant by electric current? Name and define its SI unit. In a conductor electrons are flowing from B to A. What is the direction of conventional current? Give justification for your answer.
A steady current of 1 ampere flows through a conductor. Calculate the number of electrons that flows through any section of the conductor in 1 second. (Charge on electron 1.6 X 10-19 coulomb).

Answer 1

Dear Student
Electric Current:
The amount of charge ‘Q’ flowing through a particular area of cross section in unit time ‘t’ is called electric current,
i.e. Electric current, I = Q/t
SI unit of electric current is ampere.
One ampere of current is that current which flow when one coulomb of electric charge flowing through a particular area of cross-section of the conductor in one second, i.e. 1A = 1 Cs^-1 .

In a conductor electrons are flowing from B to A then The direction of conventional current is A to B, i.e. opposite to the direction of flow of electrons.
In a metal, flow of electrons carrying negative charge constitutes the current. Direction of flow of electrons gives the direction of electronic current by convention, the direction of flow of positive charge is taken as the direction of conventional current.

Charge = q = ne
For q = 1 coulomb,
$n=\frac{1C}{1.6\times {10}^{-19}C}=6.25\times {10}^{18}ELECTRONS$

Regards