Tuesday, September 20, 2016

Electric Field & Electro Static Induction

Electric Field :
Hello all today we are going to explain about the electric field and electrostatic induction

It is found that in the medium around a charge a force acts on a positive or negative charge when placed in that medium. If the charge is sufficiently large, then it may create such a huge stress as to cause the electrical rupture of the medium, followed by the passage of an arc discharge. The region in which the stress exists or in which electric forces act, is called an electric field or electrostatic field.
The stress is represented by imaginary lines of forces. The direction of the lines of force at any
point is the direction along which a unit positive charge placed at that point would move if free to do so. It was suggested by Faraday that the electric field should be imagined to be divided into tubes of force containing a fixed number of lines of force. He assumed these tubes to the elastic and having the property of contracting longitudinally the repelling laterally. With the help of these properties,
 it becomes easy to explain



 (i) why unlike charges attract each other and try to come nearer to each other
and
(ii) why like charges repel each other
However, it is more common to use the term lines of force. These lines are supposed to emanate
from a positive charge and end on a negative charge  These lines always leave or enter
a conducting surface normally


Electro Static Induction :

It is found that when an uncharged body is brought near a charged body, it acquires some charge.
This phenomenon of an uncharged body getting charged merely by the nearness of a charged body is known as induction. a positively-charged body A is brought close to a perfectly-insulation


uncharged body B. It is found that the end of B nearer to A gets negatively charged whereas further end becomes positively charged. The negative and positive charges of B are known as induced charges. The negative charge of B is called ‘bound’ charge because it must remain on B so long as positive charge of A remains there. However, the positive charge on the farther end of B is called free charge. In Fig the body B has been earthed by a wire. The positive charge flows to earth leaving negative charge behind. If next A is removed, then this negative charge will also go to earth, leaving B uncharged. It is found that :
(i) a positive charge induces a negative charge and vice-versa.
(ii) each of the induced charges is equal to the inducing charge.

If you have any doubts please feel free to comment below

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