Question

The unit of thermal conductivity is :

• A. $J{m}^{-1}{K}^{-1}$
• B. $W{m}^{-1}{K}^{-1}$
• C. $Wm{K}^{-1}$
• D. $Jm{K}^{-1}$

Answer 1

Answer: (B)

The heat current related to difference of temperature across the length $l$ of a conductor of area $A$ is
$\frac{dH}{dt}=\frac{KA}{\ell }\Delta T$ (K = coefficient of thermal conductivity)
$\therefore K=\frac{\ell dH}{Adt\Delta T}$
Unit of K = $W{m}^{-1}{K}^{-1}$