Mechanical Engineering :: Heat and Mass Transfer
- Temperature of steam at around 540°C can be measured by
- The total radiation from a black body per second per unit area is ________ fourth power of the absolute temperature. This statement is known as Stefan Boltzmann law.
- The use of heat exchangers is made in
- The heat transfer from a hot body to a cold body is directly proportional to the surface area and difference of temperatures between the two bodies. This statement is called
- Which of the following statement is wrong?
- When α is absorptivity, ρ is reflectivity and τ is transmissivity, then for a diathermanous body,
- Planck’s law holds good for
- Thermal conductivity of a material may be defined as the
- A perfect black body is one which
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A.
The heat transfer in liquid and gases takes place according to convection |
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B.
The amount of heat flow through a body is dependent upon the material of the body |
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C.
The thermal conductivity of solid metals increases with rise in temperature |
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D.
Logarithmic mean temperature difference is not equal to the arithmetic mean temperature difference |
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A.
Quantity of heat flowing in one second through one cm cube of material when opposite faces are maintained at a temperature difference of 1°C |
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B.
Quantity of heat flowing in one second through a slab of the material of area one cm square, thickness 1 cm when its faces differ in temperature by 1°C |
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C.
Heat conducted in unit time across unit area through unit thickness when a temperature difference of unity is maintained between opposite faces |
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D.
All of the above |