Question

A metal wire has a resistance of 10.0 Ω at a temperature of 20.0 °C. If the same wire has a resistance of 12.0 Ω at 90.0 °C, what is the resistance of this wire when its temperature is -40.0 °C?

Answer 1

Let resistance at -40 ⁰C (=T₀) is R₀. Then Resistance at any temperature T is given by

for T = 20

------------(1)

for T =90

----------(2)

Dividing equation 2 by equation 1

solving we get,

0.00345

putting the value in equation 1,

R₀ = 8.28