Question

A metal wire of diameter 2.0 mm and of
length 300 m has a resistance of 1.64 ohm at
20° C and 2.42 ohm at 150° C. Find the
temperature coefficient of resistance and
resistance at 0 °C.​

Answer 1

Answer:

R150∘C=2.415=R0(1+150α),R20∘C=1.6424=R0(1+20α)

Solving these relation simultaneously, α=3.9×10−3C−1 and

R0=1.5236Ω.FromR0=ρ0(L/A), We get

1.5236=ρ0(300)π(2×10−3)2/4orρ0=1.596×10−8Wm

Thenρ20∘C=ρ0(1+20α)=(1.596×10−8)[1+(3.9×10−3(20)]

=1.720×10−8Ωm

This indicates that the meterial is copper.

HOPE THIS HELPS YOU!!

BRAINLIEST PLZ!!

Answer 2

$\huge\bigstar\underline\mathfrak\blue{Answer}$

➡Given: R0 =2.1 ohms, Rt = 2.7 ohms, T = 72.5 ° C

➡Temperature coefficient, α = ?

➡Formula : Rt = R0 ( 1+ α T)

➡Put values given above to get α.

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