Two point charges of + 2 uC and + 6...
Question
Two point charges of + 2 uC and + 6 uC repel each other with a force of 12 N. If each is given an additional charge of - 4 uC, then force will become
Fullscreen

Two point charges of ( +2 mu C ) and ( +6 mu C ) repel each other with a force of ( 12 mathrm{N} ). If each is given an additional charge of ( -4 mu C ), then force will become:-
(1) ( 4 mathrm{N} ) (attractive)
(2) ( 60 mathrm{N} ) (attractive)
(3) ( 4 mathrm{N} ) (repulsive)
(4) ( 12 mathrm{N} ) (attractive)

NEET/Medical Exams
Physics
Solution
235
Rating
3.0 (1 ratings)
Two point charges of + 2 uC and + 6 uC repel each other with a force of 12 N. If each is given an additional charge of - 4 uC, then force will become
Fullscreen

We know that the force between two charges is given by coloumbs law:
( F=frac{1}{4 pi epsilon_{0}} frac{q_{1} q_{2}}{r^{2}} )
Given that ( F=12 mathrm{N}, mathrm{q}_{1}=2 times 10^{-6} mathrm{C}, mathrm{q}_{2}=6 times 10^{-6} mathrm{C} )
( F=frac{1}{4 pi epsilon_{0}} frac{left(2 times 10^{-6}right) timesleft(6 times 10^{-6}right)}{r^{2}} )
( 12=9 times 10^{9} times frac{left(2 times 10^{-6}right) timesleft(6 times 10^{-6}right)}{r^{2}} )
( r^{2}=9 times 10^{-3} )
When an additional charge is given the force will be:
( F=frac{1}{4 pi epsilon_{0}} frac{left(2-4 times 10^{-6}right) timesleft(6-4 times 10^{-6}right)}{r^{2}} )
( F=9 times 10^{9} times frac{left(-2 times 10^{-6}right) timesleft(2 times 10^{-6}right)}{9 times 10^{-3}} )
( F=-4 N )
Therefore the new force ( =-4 mathrm{N} )

Quick and Stepwise Solutions Just click and Send Download App OVER 20 LAKH QUESTIONS ANSWERED Download App for Free