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 flow through any section of the conductor in 1 second. (Charge on electron =`1.6 times 10^-19` coulomb)

Explanation

Electric current is defined as the rate of flow of electric charge through a cross section of a conductor. IF Q charge passes through a section of a conductor in time t, then current `I=Q/t`
Si unit of electric current is an ampere (A). Current is said to be one ampere, if rate of flow of charge through a cross section of conductor be 1 coulomb per second.
Direction of conventional current is taken as the direction of flow of positive charge or opposite to the direction of flow B to A Then the direction of conventional current will be form A to B.
Here current I=1A time t=1s and charge on electron `e=1.6 times 10^-19C`. Let n electrons flow through a section of conductor so that charge passing through the section is Q =ne.
`therefore I=Q/t=(n e)/t implies n= (I t)/e=(1 times 1)/(1.6 times 10^-19)=6.25 times 10^18`