Question

If the temperature difference on the two sides of a wall increases from $100{}^\circ C$ to $200{}^\circ C$ , its thermal conductivity

• A. remains unchanged
• B. is doubled
• C. is halved
• D. becomes four times

Answer 1

Answer: (A)

remains unchanged

Answer 2

The coefficient of thermal conductivity of a material is the amount of heat flowing in $1\,\,s$ through a rod of that material of $1\,\,m$ length and $1\,\,{{m}^{2}}$ area of cross-section in the steady state; when the difference of temperatures between the two ends of the rod is ${{1}^{o}}C$ and the flow of heat is normal to the end faces of the rod. Coefficient of thermal conductivity $K$ is a constant, whose value depends upon the material of the rod. Hence, even if temperature increases or decreases, its thermal conductivity remains unchanged.