Electric Potential
The electric potential at a point is defined as the work done in moving a unit positive charge from infinity to that point.
Potential Difference
Potential Difference between two points on a conductor carrying current is defined as the work defined in moving a unit positive charge from one point to the other.
Potential Difference = \(\frac{\text { Work Done }(\mathrm{W})}{\text { Charge }(\mathrm{Q})}\)
Example 1.
How much energy is given to each coulomb of charge passing through a 6 V battery?
Answer:
It is given that charge q = 1 C, V = 6V.
We know that work done W = q V = 1 × 6J = 6J.
Therefore, 6J energy is given to one coulomb of charge passing through a 6 V battery.
Volt: One volt is the potential difference be¬tween two points in a current-carrying conduc¬tor when 1 Joule of work is done in moving a charge of 1 Coulomb from one point to another.
1 Volt = \(\frac{1 \text { Joule }}{1 \text { Coulomb }}\)
Voltmeter: It is an instrument to measure the potential difference. The voltmeter is always connected in parallel across the points between which the potential difference is to be measured.