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? |
3Q/8 3Q/4 3Q/2 Q/2 |
3Q/4 |
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. |