Materials and Components - Engineering

Q1:

As per Matthiessen's rule, the total resistivity r of a conductor can be written as r = ri + aT, where ri and a are constants and T is absolute temperature. At very low temperatures

A aT = 0

B aT > ri

C aT ∼ ri

D aT < ri

ANS:D - aT < ri

At very low temperatures a T → 0. Since resistivity has a finite value even at low temperature, a T < ri.