Read the passage and answer the question.
Two spherical conductors B and C having equal radii and carrying equal charges in them repel each other with a force F, when kept apart at some distance. A third spherical conductor having same radius as that of B but uncharged, is brought in contact with B, then brought in contact with C and finally removed away from both. The new force of repulsion between B and C is:
Following from last question, what is the charge on A?
Answer & explanation
Correct answer: option 2
The correct answer is Option 2: 3Q/4
The initial charges on B and C are equal, say Q each.
When the uncharged conductor A touches B, Charge gets equally shared (since radii are same):
B = Q/2, A = Q/2
A now touches C (which has charge Q)
Total charge = Q/2 + Q = 3Q/2
This gets equally divided:
A = 3Q/4, C = 3Q/4
Final charges:
B = Q/2, C = 3Q/4, A = 3Q/4
Thus, the charge on A is 3Q/4.