Question Detail
Question
Two wires A and B, same length, same material, circular cross-section. Wire A has 4× resistance of wire B. Diameter of B is how many times greater than A?
Correct Answer
Option C is the correct answer.
Detailed Explanation
R = ρL/A, A ∝ d². R_A/R_B = (d_B/d_A)² = 4 → d_B/d_A = 2.
Hint
R ∝ 1/d².