In order to understand electric potential, let’s took some observations. As we aware that water flows when there is a difference in water levels in two similar pipes from higher level to lower level. As shown in the following figure.
and heat flows when there is difference in the temperature from high temperature to low temperature. Similarly current flows when there is potential difference from high potential to low potential. So potential in electricity is used in the same sense as temperature is used with heat and as surface level of liquid used with flow of liquid.
Measurement Of Potential:
“The potential at any point in the electric field is defined as the work done in bringing a unit positive charge from infinity to that point.”
Mathematically, v= W/q0
where, “w” is the work done in bringing a unit positive charge and q0 is magnitude of the test charge.
The potential of a charged particle is measured by assuming the Earth’s potential zero. If the potential of an object is more than the potential of the Earth then it has a positive potential otherwise it has negative potential.
The amount of work done in moving a unit positive charge from one point to another point in an electric field is called the potential difference between these two points
potential difference is a scalar quantity. The S.I. unit of potential difference is “volt”. Potential difference between two points is measured by a device called as “voltmeter”.Voltmeter is joined parallel between the points whose potential difference is to measured.
The rate of flow of charge is known as electric current
The S.I. unit electric current is ampere. If a charge of “Q” coulomb flows through a conductor for “t” second, then the electric current flowing through it is given by,
Current, I= Q/t
Ohm’s law is given by a German Scientist Georg Simon Ohm in 1827 which states that the electric current flowing in a conductor is directly proportional to the potential difference across the ends of the conductor, provided the physical conditions of the conductor remains the same.
If “I” current is flowing through the conductor when “V” potential difference is applied then by Ohm’s Law.
Where, R is the constant called resistance of the conductor whose unit is “ohm”.
Thermal Effect Of Electric Current:
When electric current is passed through an electric bulb it glows and becomes hot after some time. In the same way when electric current flows through high resistance wire like nichrome it becomes red hot and gives out heat. This is known as the heating effect of current.
According to this law the amount of heat produced in a conductor is directly proportional to the square of current flowing through it,to the resistance of the conductor and to the time for which the current flows.
H = I2RT
Power is defined as the rate of doing work. When an electric current flows through a conductor some amount of electric current is used in doing work. So we can define electric power as the amount of electric energy used in doing work in one second or we can define electric power as the rate at which electric energy dissipated. S.I. unit of electric power is “watt”.
Formula For Calculating Electric Power
Electric Power, P = electric potential * electric current