Download Aptitude Crack
img not found img not found

Heat Transfer - Engineering

Q1:

In Fourier's law, the proportionality constant is called the

A heat transfer co-efficient

B thermal diffusivity

C thermal conductivity

D Stefan-Boltzman constant

ANS:C - thermal conductivity

In Fourier's law of heat conduction, the proportionality constant is called the thermal conductivity (𝑘k). Fourier's law states that the rate of heat transfer (𝑄Q) through a material is directly proportional to the temperature gradient (𝑑𝑇/𝑑𝑥dT/dx) across the material, and is given by: 𝑄=−𝑘𝑑𝑇𝑑𝑥Q=−kdxdT​ Where:

  • 𝑄Q is the rate of heat transfer (W),
  • 𝑘k is the thermal conductivity of the material (W/m·K),
  • 𝑑𝑇dT is the temperature difference (K), and
  • 𝑑𝑥dx is the distance over which the temperature gradient occurs (m).
Therefore, the correct term for the proportionality constant in Fourier's law is: thermal conductivity.