Electric Circuit
(i)EMF: Electromotive force (emf) is the force that causes an electric current to flow in an electric
circuit.The S.I. Unit of EMF is volt (V).
(ii) Potential difference: Potential difference between two points in an electric circuit is that difference in their electrical state which ends to cause flow of electric current between them.
The S.I. unit of potential difference is volt (V)
(iii) Electric Current: The electric current is defined as the rate of flow of electric charge or electrons,
Its S. I. unit is Ampere (A).
(iv) Electric Power: The rate at which work is done in an electric circuit is known as electric power.
i.e. Electrical power=
Power = voltage x current
P=VI
P = I2R
P = V2/
R
The basic unit of electric power is watt.
One Watt: The power in electric circuit is one watt if a electric potential of 1 volt causes 1 ampere electric current to flow through the circuit.
(v) Electrical Energy: The total amount of work done in an electric circuit is called electrical energy. Electrical Energy = Voltage x Current x time
The unit of electric energy is watt-second
Ohm’s Law
Ohm's law states that "The potential difference between the two ends of a conductor is directly proportional to the current flowing through it, provided it's temperature and other physical parameters remains unchanged".
That is, V α I
V=RI
where, R is the resistance between these two points.
Voltage= Current× Resistance
V= I×R
V= voltage, I= current and R= resistance
The SI unit of resistance is ohms and is denoted by Ω
Limitations: Resistance, Temperature, Physical condition should remain constant.
