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.

INTRODUCTION:
It is the fact that the gases have not fixed volume or shape and their volume can be change by the increase or decrease the pressure or temperature.the behaviour of a gas is described by the four variables pressure, volume, temperature and the mass of a gas.

BOYLES's LAW:

INTRODUCTION:

The law was given by Robert Boyle in 1660. He found experimently the relation between the Pressure and Volume at constant Temperature.

STATEMENT:

"For a given mass of a gas the volume is inversely proportional to the pressure exerted by it when the temerature of a gas is kept constant"

MATHEMATICALLY :

Let 'V' is the Volume of a gas which exerts a pressure 'P' on its surrounding at constant.       
Then According to the Boyle's Law

   V α 1/P 

OR

VP= Constant

that is the product of the pressure and volume is constant at constant temerature.

FOR N states of a GAS:

Consider N states of gas where the pressure and volume changes but temperature is kept constant.

P1V1=P2V2=P3V3..............PNVN

Where:

P1=Pressure at 1st state

P2=Pressure at 2nd state

P3=Pressure at 3rd state

PN=Pressure at Nth state 

V1=Volume at 1st state

V2=Volume at 2nd state

V3=Volume at 3rd state

VN=Volume at Nth state

if the mass of gas is not kept constant.

   P1V1/m= P2V2/m = P3V3/m =............. PnVn/m

where 'm' is the mass of a gas.

GRAPHICALLY:

let we take pressure at Y-axis and the Volume at X-axis then the Graph will be:

The Hyperbolic Curve is formed.

CHARLES LAW:

INTRODUCTION:

The law is given by CHARLES as known as the charles law which gives the relation between the volume and Temperature at Constant Pressure.

STATEMENT:

"For a given mass of a gas the volume is directly proportional to the temperature of a body when the pressure is kept constant"

MTHEMATICALLY:

let us consider a gas has a volume 'V" and at temerature 'T' where as the pressure of the gas is kept constant"

then according to the charles law:

V α T

OR

V/T = constant
that is the ratio of volume and pressure is constant at constant temperature.

FOR N STATES OF GAS:

V1/T1 =V2/T2 = V3/T3..........Vn/Tn

If the mass of gas is not constant then,

                              V1/mT1 =V2/mT2 = V3/mT3..........Vn/mTn

GRAPHICALLY: