If a charge Q flows through the cross-section of a conductor in time t, the current I then I=Q/t. explain
Answers
Consider a simple circuit connected with a cell, plug key and a bulb in series with an ammeter to measure the current. Insert the plug key and observe the flow of current. We can see that there is an electric current flowing in the circuit, which turns on the bulb. The charges are supplied by the cell which set up the electric current in the circuit.
Electrons were not known at the time when the phenomenon of electricity was first observed. So, an electric current is considered as the flow of positive charges. The direction of flow of positive charges was taken to be the direction of electric current which is opposite to the direction of the flow of electrons.
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. The coulomb is equivalent to the charge contained in nearly 6 x 10 to the power 18 electrons. The electric current is expressed by a unit called ampere. One ampere is constituted by the flow of one coulomb of charge per second. An instrument called ammeter measures electric current in a circuit. It is always connected in series in a circuit the current is to be measured.