Question

The resistance of a metal wire of length one metre is 25 ohm at 20 degree Celsius if the diameter of the wire is 0.3 mm . what must be the resistivity of metal at that temperature

Answer 1

Answer:

Explanation:

R = 25 ohm,

L = 1 m,

D = 0.3 mm = 3 x 10-4 m

radius r = D/2 = 1.5 x 10-4 m

A = $\pi r^{2}$ = $\pi$(1.5 x 10-4)(1.5 x 10-4 ) =  $\pi$* 2.25 x 10-8 m2

resistivity = R X A / L = 25 x $\pi$ * 2.25 x 10-8 / 1

resistivity = 1.76 x 10-6 ohm-m

Answer 2

Answer:

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