Question

The resistance of a platinum wire is 5ohm at ice point and 5.5ohm at steam point.find the temperature at which resistance of wire is 5.8ohm

Answer 1

Explanation:

Given,

Resistance at ice point,R0=5Ω,

Resistance at steam point,R100=5.25Ω,

Resistance when dip in unknow,R0=5Ω,R100=5.25Ω,Rt=5.5Ω

R100=R0(1+α100)

α=R0×100R100−R0=5×1005.25−5=5×10−4 oC−1  

Let the temperature of hot bath = toC

Rt=R0(1+αt)

t=RoαRt−R0=5×(5×10−4)5.5−5=