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Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning - Discussion

Discussion Forum : Heat Transfer, Refrigeration and Air Conditioning - Section 1 (Q.No. 3)
Heat Transfer, Refrigeration and Air Conditioning
3.
Which of the following statement is wrong?
The heat transfer in liquid and gases takes place according to convection.
The amount of heat flow through a body is dependent upon the material of the body.
The thermal conductivity of solid metals increases with rise in temperature,
Logarithmic mean temperature difference is not equal to the arithmetic mean temperature difference.
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
31 comments Page 3 of 4.
Ravi kumar said:   1 decade ago
For pure metals temperature increases k value decreases for alloys it will increases.
Bir Bahadur Singh(Prakash Kumar) said:   1 decade ago
Thermal conductivity is inversely proportional to temperature gradient.
Manish said:   1 decade ago
Thermal conductivity is the property of any material which show the speed of vibration and electron transfer from one point to another.
Mohnesh said:   1 decade ago
Thermal conductivity is property. But it is not change with respect to temperature.
Jyosna said:   1 decade ago
Thermal conductivity is inversely proportional to the temperature, according to fourier's law.
SAIKUMAR said:   1 decade ago
In solids the molecules are closely packed. The heat transfer more because this arrangement. Hence the conductivity increases with increases with increase in temperature.
Satish said:   1 decade ago
K(Thermal conductivity)inversely proportional to temperature(T)(Fourier's law of heat conduction).
RS RAJPUT said:   1 decade ago
Heat transfer in metal can be,

1. By lattice vibration.

2. By free electron transfer(free electron provide the heat flux in the direction of decreasing temperature).

(Factor two is more dominating to factor one but both act simultaneously).

According to second point. If we increase the temperature of metal these decrease the tendency free moving electron.

These may be reason for decreasing conductivity of metal.
Swapnil said:   1 decade ago
Thermal conductivity is inversely proportional to temperature(According Fourier's law of heat conduction).
Narendra said:   1 decade ago
Thermal conductivity is proportional to square root on I/M.
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