Potential Difference, Electromotive Force and Ohm's Law

Things to remember

• The e.m.f. of an electric source is the rate at which energy in a non-electrical form is converted into an electrical form during the passage of unit positive charge through it.
• Voltmeter is an electrical device which measures potential difference between any two points in an electric circuit.
• According to the Ohm's law, 'The electric current passing through a conductor is directly proportional to the potential difference across its two ends at a constant physical condition.'
• Resistance is the ratio of the potential difference across its two ends to the electric current flowing through it.