Two positive point charges +4Q and +Q are separated by distance of 'a' units. What is magnitude and nature and also position of charge such that system is in equilibrium?

Asked by dinesh malik | 5th Apr, 2014, 05:53: PM

Expert Answer:

Let the charge'q' be placed at a point O along the line joining the other two charges.
For a system of charges to be in equilibruim.
net force on all the three charges must be zero.
If charge q is positive in nature,it will experience forces due to other two charges in opposite directions and hence net force on charge q may be 0.But the force on the charge 4Q and Q will not be 0.It is because the force on a charge Q or 4Q due to other two charges will act in same direction.
However if charge q placed is negative,then on a charge Q or 4Q ,forces due to other two charges will act in the opposite direction.Hence the third charge placed must be negative.
 
 

Answered by  | 7th Apr, 2014, 11:56: AM

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