. 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?

 

Best Answer

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.

 

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