Thursday 16 March 2017

Explain Difference Between EMF and Voltage???

Definition of Voltage :

Voltage is defined as the energy requires to moves the unit charge from one point  to another. It is measured in volts and represented by the symbol V. The voltage is caused by the electric and the magnetic field.

The voltage is developed between the ends (i.e. the cathode and anode) of the source. The potential of the positive end point of the source  is higher as compared to the negative points. When the voltage develops across the passive element, then it is called the voltage drops. The sum of the voltage drops in a circuit is equal to the EMF according to Kirchoff’s law.

Definition of EMF :

The energy supply from the source to each coulomb of charge is known as the EMF. In other words, it is the energy supply by some active source such as the battery to the unit coulomb charge. The EMF stands for the electromotive force. It is measured in volts and represented by the symbol ε.

The electromotive force of the above circuit is represented by the formula


Where,

  • r – internal resistance of the circuit.
  • R – External resistane of the circuit.
  • E – electromotive force.
  • I – current

Comparison of  EMF & Voltage :

One of the major difference between the EMF and voltage is that EMF is the energy supplied to the charge, whereas the voltage is the energy requires to move the unit charge from one point to another. The other differences between them are explained below in the comparison chart.

Basis for Comparison EMF Voltage
Definition The amount of energy supply by the source to each coulomb of charge. Energy use by unit charge to move from one point to another
Formula E= I ( R + r ) V=IR
Symbol ε V
Measure Measure between the end point of the source, when no current flows through it. Measure between any two points.
Source Dynamo, electrochemical cell, transformer, solar cell, photodiodes etc. Electric and magnetic field

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Explain Difference Between EMF and Voltage???
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