. How does the resistance
(a) How does the resistance of a wire depend on its radius? Explain your answer.
(b) Two copper wires are of same length, but one is thicker than the other. Which will have more resistance?
Resistance of a wire varies inversely as the area of cross section of the wire i.e.,
R ∝ 1 / a
R ∝ 1 / π2
Resistance of a wire is directly proportional to its length, i.e., R ∝ l and varies inversely as the area of cross section of the wire i.e., R ∝ 1 / a or R ∝ 1 / πr2
Since the resistance is inversely proportional to area of cross section, hence thin wire will have more resistance.