Question

A wire has a resistance of 5.5 Ω at 19^oC and 21.5 Ω at 200^oC. Find the temperature coefficient of resistivity(α) of the material.

(a) 0.016 ^oC^-1

(b) 0.160 ^oC^-1

(c) 1.600 ^oC^-1

(d) 16.00 ^oC^-1

I have been asked this question in an international level competition.

Enquiry is from Current Electricity topic in portion Current Electricity of Physics – Class 12

Answer 1

Right choice is (a) 0.016 ^oC^-1

Explanation: Temperature coefficient α=\(\frac {(R_2-R_1)}{R_2(T_2-T_1)}\).

α = \(\frac {(21.5-5.5)}{(5.5(200-19))}\)

= 0.01607 ^oC^-1.