1)

A wire has resistance of 3.1Ω  at 300C  and 4.5Ω  at 1000C . The temperature coefficient of resistance  of the wire is 


A) 0.00120C1

B) 0.00240C1

C) 0.00320C1

D) 0.00640C1

Answer:

Option *

Explanation:

 Given,

 t1=300C

R1=3.1Ω

t2=1000C

R2=4.5Ω

 we know that,

 temperature  coefficient of resistance,

 α=R2R1R1t2R2t1=4.53.1(3.1)(100)(4.5×30)

  = 1.4310135=1.4175=0.0080C1