Which one of the following is the SI unit of the thermal conductivity of a material?
Wm'K~!
Wm/K
WmYK™?
Js'm'K
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC NDA-2 – 2015
The SI unit of thermal conductivity (k) is Watt per meter-Kelvin (W/(m·K)) or W·m⁻¹·K⁻¹. This unit comes from Fourier’s law of heat conduction, which states that the rate of heat flow (Q) is proportional to the area (A), the temperature gradient (dT/dx), and the thermal conductivity (k): Q = -k * A * (dT/dx). Rearranging for k, k = Q / (A * (dT/dx)). The units are W / (m² * (K/m)) = W / (m * K) = W m⁻¹ K⁻¹. Assuming the symbols in option A represent W m⁻¹ K⁻¹, it is the correct unit.