Electric current

Current 

If a net charge Q, flows across any cross-section of a conductor in time t, then the current I, through the cross-section is I = Q/t  The SI unit of electric charge is coulomb (C), which is equivalent to the charge contained in nearly 6 × 10×18 electrons. (We know that an electron possesses a negative charge of 1.6 × 10–19 C.) The electric current is expressed by a unit called ampere (A)