Difference Between Electromotive force and Potential Difference

Electromotive force and potential difference are not same. They have following differences below:

Electromotive force

1. The potential difference between the two terminals of a cell is called electromotive force in an open circuit.
2. Electromotive force transmits current both inside and outside the cell.
3. Electromotive force emf is the cause.
4. Electromotive force is always greater than potential difference.
5. Electromotive force creates potential difference entire the circuit.
6. Electromotive force does not depend on the resistance of the circuit.
7. Electromotive force remains constant.
8. The part of the circuit where electrical energy is created from any other energy then that part contains the source of Electromotive force.

Potential difference

1. Bringing a unit positive charge from one point to another point in a circuit is called potential difference between two points.
2. Potential difference current transfers between any two points in the circuit.
3. Potential difference is the result.
4. Potential difference is always less than electromotive force.
5. Potential difference takes place between any two points in the circuit.
6. Potential difference of two points depends on the resistance of those points.
7. It does not remain constant.
8. Potential difference exists in the part of the circuit where electrical potential energy is transformed into another form of energy.

Relation Between Cp & Cv

to understand the relation between Cp and Cv we must know that what they are:

Cp:

 The amount of heat required to raise the temperature of a system at constant pressure.

Cv:

 The amount of heat required to raise the temperature of a system at constant volume.

RELATION:

If the system is set at constant pressure and heat is supplied to it according to first law of thermodynamics that heat converted into some amount of work and its internal energy increases and then temperature

Amount of heat(Q) = Use ful Work(W) + Raise in internal energy(U)

If the system is set at constant volume and then heat is supplied to it according to first law of thermodynamics no work be there and all heat energy is used to increase its internal energy and temperature.

Amount of heat(Q) =  Raise in internal energy(U)

the raise in internal energy is the raise in temperaure.

Because internal energy is directly proportional to the absolute temperature.