What is EMF? We explain simply and clearly

Physics - is an amazing science, the study of which reveals to us an understanding of what laws there is a particular process. But in order to more deeply immersed in this wonderful world, we must not simply know and understand the basic laws. In this article I will try to explain as simply, what it is EMF - electromotive force. So, let's begin.

What is EMF? We consider the definition

So, to start, let's refresh (or read for the first time) what the EMF. EMF (electromotive force) - is a scalar physical quantity that characterizes the work of external forces acting in the electric circuits of direct and alternating current.

This value is measured in volts as well as VoltageBut this does not mean that EMF and Voltage -This is the same.

Voltage - a physical quantity which characterizes the effect of electric fields on charged particles.

Explain on the fingers what EMF

To understand, let's consider the following example. Let's take a suspended conductor and inform him potential difference, i.e. at one end it will have a positive charge and the other negative.

Since we obtain a chain, the ends of which there is a potential difference on the conductor a current flows, and it will flow as long as the potentials at the ends of the conductor does not has adjusted.

And now let's water tower, in which the tank is full of water.

And the water pressure correlate with stress. After all, if you open the valve at the bottom of the tower, the first pressure is strong, but with water over time completely ceases to flow, i.e. the pressure in the barrel (the potential difference in the case of the conductor) will be zero.

Now ask yourself the question: "What should be done so that the water tower does not drop the water pressure?"

That's right, put to pumps that will maintain a constant water level. They (the pumps) will perform the work.

So it is our Electromotive force - is none other than the operation (pumps, water tower), which is performed by outside forces in order to maintain the potential difference in the chain.

Nature EMF

EMF from different sources is generated by various causes, and the following types of EMF:

1. Chemical. This type of EMF generated as a result of the chemical reaction. It is widely used in batteries and accumulators.

2. Thermal. This type of EMF generated when two elements having different temperatures are connected at one point. Peltier element.

3. Induction EMF. Formed when in the magnetic field of the conductor rotation. When this electromotive force is induced when the conductor crosses the magnetic field lines, or vice versa conductor itself is fixed and changes the magnetic field around it.

4. Photovoltaic EMF. This type is formed when there is internal or external photoelectric effect.

5. Piezoelectric EMF. This type EMF occurs when there is compression or tension special materials.

conclusion

As you probably already realized EMF - a force that is not electrical in nature, but it is responsible for the flow of electric charge in a closed circuit.

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