Electrostatics Question 221

Question: Two equally charged, identical metal spheres A and B repel each other with a force ‘F’. The spheres are kept fixed with a distance ‘r’ between them. A third identical, but uncharged sphere C is brought in contact with A and then placed at the mid-point of the line joining A and B. The magnitude of the net electric force on C is [UPSEAT 2004; DCE 2005]

Options:

A) F

B) 3F/4

C) F/2

D) F/4

Show Answer

Answer:

Correct Answer: A

Solution:

Initially F=kQ2r2 ……. (i)

Finally Force on C due to A, FA=k(Q/2)2(r/2)2=kQ2r2

Force on C due to B, FB=KQ(Q/2)(r/2)2=2KQ2r2

Net force on C, Fnet=FBFA=kQ2r2=F



NCERT Chapter Video Solution

Dual Pane