What is Electric Field

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Forces come in two categories: Contact Forces and Non-Contact Forces. Contact Forces are quite usual and customary to us. Electric Force and Gravitational Force are examples of non-contact forces.Non-contact forces or Action-at-a-distance forces requires a more difficult explanation.

Example of Non Contact force is that the Moon has a gravitational field around it,and if we get close to the moon,it will pull us down to its surface.

Scientists understood why forces acted the way they did when objects touched.The idea that confused them was forces that acted at a distance without touching them.To help them explain what was happening they used the idea of "field". They imagined that there was an area around the object,and anything that entered would feel a force.

An electric field describes the area near any electrically charged object. It is also called an electrostatic field.Any other charge that enters the area will feel a force.

A normal field is a vector,and is represented by arrows. A field vector shows the direction of effect of an object entering the field.The direction of Earth's gravitational field is downwards.For an electric field,things are little complicated,since they are two kinds of charges and some combinations attract and some combinations repel.In order to be in agreement with each other,physicists decided that they will always use positive charge as test particle to determine the direction of the field. So if the central charge was positive,and if we put another positive charge near it,that second charge will be repelled outward. So,the field vectors for a central positive charge point outward.If the central charge is negative,and a positive charge placed nearby would be attracted towards the center charge,so the field vectors for a central negative charge  point inward.



As fields are directly related to the forces they exert,their strength decreases with distances and increases with size of the charge producing of the field.





References:
1.http://www.physicsclassroom.com/Class/estatics/u8l3a.cfm
2.http://www.physics4kids.com/files/elec_field.html
3.

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