Discussion :: Heat and Mass Transfer
- Which of the following statement is wrong?
A.
The heat transfer in liquid and gases takes place according to convection |
B.
The amount of heat flow through a body is dependent upon the material of the body |
C.
The thermal conductivity of solid metals increases with rise in temperature |
D.
Logarithmic mean temperature difference is not equal to the arithmetic mean temperature difference |
Answer : Option C
Explanation :
For metals, the thermal conductivity is mainly a function of the motion of free electrons. As the temperature increases, the molecular vibrations increase (in turn decreasing the mean free path of molecules). So, they obstruct the flow of free electrons, thus reducing the conductivity
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