What is the thermal conductivity of a perfect heat insulator ?
Correct answer: D. Zero
- A. Between 0 and ∞
- B. One
- C. ∞
- D. Zero
Explanation
A perfect insulator permits no conductive heat flow, so Fourier’s law requires its thermal conductivity to be zero. Real insulating materials have small, but nonzero, conductivity.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
Practise Heat Transfer Operations
645 free Heat Transfer Operations MCQs from Chemical Engineering, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Chemical Engineering questions like this
Chemical Engineering is on this paper prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for it.
More Heat Transfer Operations questions
The ratio of momentum diffusivity to thermal diffusivity is the ______________ number?
A metal ball of radius 0.1 m at a uniform temperature of 90°C is left in air at 30°C. The density and the specific heat of the metal are 3000 kg/m3 and 0.4 kJ/kg.K respectively. The heat transfer co-efficient is 50 W/m2.K Neglecting the temperature gradients inside the ball, the time taken (in hours) for the ball to cool to 60°C is_________________?
Heat transfer occurs by natural convection because change in temperature causes difference in__________________?
The value of Stefan-Boltzmann constant in SI unit is_________________?
Air is best heated with steam in a heat exchanger of__________________?
Which is the most suitable for the concentration of foamy & frothy liquors ?