## Thursday, November 22, 2012

### Superposition Principle

The electrostatic force experienced by a charge due to other charges is the vector sum of electrostatic forces due to these other charges as if they are existing individually.

In the present example, a = 1 and b = 2 to 5. If the force is to be found on 2nd charge,then a = 2 and b = 1 and 3 to 5.

Note:
The interactions must be on the charge which is to be studied due to other charges.
The charge on which the influence due to other charges is to be found is assumed to be floating charge and others are rigidly fixed. For eg. 1st charge (floating) is repelled away by q2 and q4 and attracted towards q3 and q5.
The interactions between the other charges (among themselves) must be ignored. i.e. F23, F24, F25, F34, F35 and F45 are ignored.
Superposition principle holds good for electric field also.
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Some of these questions which may be asked in your Board Examination 2012-2013

Q1: what are the characteristic of charges acquired by the objects on rubbing against each other?

Q2: Who suggested first that there are two kinds of charges?

Q3: How can you show that there are two types of charges?

Q4: An ebonite rod is rubbed with the fur or wool. What type of charges do they acquire?

Q5Is mass of body affected on charging?

Q6: What is the polarity of charge?