A small metallic sphere is held in a non-uniform electrostatic field as shown in the figure. Also shown are two points P and Q on the surface of the sphere. Which one of the following statements is true for the sphere?
Sphere does not experience a force in the field.
Surface charge density at point P is positive while at point Q is negative.
Sphere experiences a force towards the left.
Sphere experiences a force towards the right.
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC Geoscientist – 2024
A conductor in an electrostatic field is an equipotential surface, and the electric field lines are perpendicular to its surface. In a non-uniform field (indicated by varying density of field lines), the side facing the stronger field region (denser lines, like point P) will accumulate induced charge opposite to the field source, and the opposite side (sparser lines, like point Q) will accumulate the same type of charge as the source. The forces on these induced charges are F = qE. Since the field strength E is non-uniform, the force on the induced charge in the stronger field region will be greater.