➖If the electric charge flows through a conductor, such as a metallic wire, it is known as the electric current in the conductor.
➖A continuous and closed path of an electric current is known as an electric circuit.
➖In an electric circuit, usually, the direction of electric current known as positive charges, is considered as opposite to the direction of the flow of electrons, which are considered as negative charges.
➖The SI unit of electric charge is coulomb (C).
➖Coulomb is equivalent to the charge contained in closely 6 × 1018 electrons.
➖The electric current is expressed by a unit known as an ampere (A).
➖It was named after the French scientist Andre-Marie Ampere.
➖One ampere constitutes by the flow of one coulomb of charge per second, i.e., 1 A = 1 C/1 s.
➖The instrument that measures electric current in a circuit is known as ammeter.
➖The electric current flows in the circuit starting from the positive terminal to the negative terminal of the cell through the bulb and ammeter.
✍️Electric Potential and Potential Difference
➖The electrons of a conductor move only if there is a difference of electric pressure, known as the potential difference.
➖The chemical action within a cell produces the potential difference across the terminals of the cell. Further, when this cell is linked to a conducting circuit element, the potential difference sets the charges in motion in the conductor and generates an electric current.
➖Alessandro Volta 1745–1827, an Italian physicist, first noticed the electric potential difference; therefore, the SI unit of electric potential difference is given volt (V).
➖The instrument that measures the potential difference is known as the voltmeter.
➖The rate at which electric energy is dissipated or consumed in an electric circuit is known as electric power.
➖The SI unit of electric power is watt (W).