1.
The correct answer is (A).
When a conducting sphere is placed in an electric field, the charges inside the sphere will redistribute themselves in such a way that the net electric field inside the sphere is zero. Therefore, the charge on the sphere at any instant will be proportional to the electric field.
2.
The correct answer is (A).
The force experienced by a test charge q placed at the center of a uniformly charged ring is zero. This is because the electric field at the center of a uniformly charged ring is zero.
3.
The correct answer is (C).
The electric field at a point P, a distance r from the center of a conducting sphere of radius R, will be proportional to r2. This is because the electric field due to a point charge is inversely proportional to the square of the distance from the charge.
