electrostatics

3 equal charges q are places at the corners of an equilateral triangle f side a . A charge Q is placed such that its distance 4m each corner is r then the force xperienced by Q WILL BE????

2) 2 parallel plate capacitors of capacitances c n 2c are connectd in paralel n charged to a potential difference V by a battery . the battery is then disconnectd n space b/w the plates f capacitor c is completely filled with a material of dielectric constnt k the pd across capacitors now bcums???

2 Answers

49
Subhomoy Bakshi ·

first of all the thing one should realise that the required position of the charge Q will lie on the line of intersection of the planes which are the perpendicular bisector of the lines joining any of the 2 charges.

or it is a line through the circumcentre and perpendicular to the plane formed by the three charges.

(these are true for any type of triangle...now coming back to this problem)

considering one charge q, the circumcentre C and the charge Q.

next u shud realise that the force F will be same for all three...

and we need to add only the upward components since the rightward ones would sum up to 0 (by symmetry)

Thus we need to add up the three Fsinθ

so net force = 3Fsinθ = 3. qQ4πεor2.sin(cos-12a3r)

Thats the answer...

1
shreeni deshi ·

tnq ..tnks alot!!!

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