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How does a battery create potential difference?

How battery creates potential difference??? …plz give me a detailed description of it.

Posted by Arti.


Potential difference means “Difference in electrical potential. In an electrochemical cell, the potential difference is created by chemical reactions. In a cell there are two electrodes and they are maintained at different potentials by the chemical reactions taking place.

Please refer to the following links for more information.

Working of a microphone

How does a microphone do its work? Please explain me and can you give me answer in language Hindi I’m very thankful to you. (Shubham Agnihotri asked)

inside a microphone
Microphone is a transducer (a device which converts energy from one form to another). The microphone converts sound energy to mechanical energy and then to electrical energy.

When we speak into the mic, the vibrations of the air produced by the sound make the diaphragm of the mic vibrate. A coil attached to the diaphragm vibrates together with it. The coil is moving in a strong magnetic field produced by a permanent magnet. Whenever the magnetic flux linked with coil changes an emf is induced in it. Therefor when we speak into the mic, an emf varying similar to the pressure variations produced by our sound is produced across the coil by electromagnetic induction.

If the ends of the coil is connected to an amplifier this can be amplified and can be send to the loudspeaker. The working of the loudspeaker is just the reverse of that of the microphone. I converts the electrical signal to sound signals.

(Please use Google Translate  or Click Here to get the Hindi Version)

Differences Between EMF and Potential Difference

What is main relationship between EMF and potiential difference?

Answer: The question is already answered at http://askphysics.com/difference-between-emf-and-pd/

Electrons and flow of electrons – Did you have this doubt before?

“When an electric cell is connected to a circuit, electrons flow away from the negative terminal in the circuit. But within the cell, electrons flow to the negative terminal. Explain?

Answer: The question seems to be the result of some misconceptions. If we consider an electrochemical cell, it is the chemical reactions which develops and maintains the potential difference between the terminals of the cell. When externally connected, the electrons flow from the negative terminal (at lower (+) potential, to higher(+) potential). When the electrons start moving, the potential difference tends to decrease and therefore chemical reaction starts/speeds up to keep the potential difference constant.

But as the movable charges inside an electrolyte are ions, they cannot move as freely as the electrons in a metal. The opposition to the movement of ions results in a resistance inside the cell itself and is called internal resistance.

Difference between emf and pd

ananthesh asked:

“can you please explain about emf and PD of a cell?”


EMF stands for electromotive force.

EMF of a cell is equal to the potential difference between the two terminals of a cell when no current is drawn from it.

Pd (potential difference) between any two points on a circuit is defined as the work done per unit charge in carrying a positive test charge from one point to the other. With reference to a cell, the potential difference between the terminals of a cell when a current is drawn from it is called terminal voltage.

How can the electric current in a circuit be kept continuous?

Susmita asked:

  1. What is Current?
  2. How can electric current in a circuit be kept continuous?



The word current means flow.

Electric Current refers to charges in motion. The most common way of producing current is by applying a potential difference across the terminals of a conductor. Then the free electrons in the conductor drifts towards the positive terminal.

The current in the circuit can be kept continuous by providing a constant potential difference between two points of the circuit. This is usually done by connecting the ends of the circuit to the terminals of an electrochemical cell (which converts chemical energy to electrical energy) or a dynamo (which converts mechanical energy to electrical energy)

Please refer the following links for more information

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