A charge of 20 μC lies at the centre of a square. Work done in carrying a charge of 5 μC from one corner of the square to the diagonally opposite corner is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 0 J
The work done in moving a charge q between two points is \( W = q(V_B - V_A) \), the electrostatic force being conservative. The centre of a square is at the same distance from all four corners, so the potential due to the 20 μC charge is the same at every corner.
\( V_B - V_A = 0 \Rightarrow W = 5\,\mu\mathrm{C}\times0 = 0\,\mathrm{J} \)