Question Detail
Question
Two wires A and B have identical lengths and material. Wire A has four times resistance of B. How many times greater is diameter of B than A?
Correct Answer
Option C is the correct answer.
Detailed Explanation
R = ρL/A. R_A = 4R_B => A_B = 4A_A. Since A ∝ d², d_B = 2d_A.
Hint
Resistance is inversely proportional to cross-sectional area.