Q. The heat flux (from outside to inside) across an insulating wall with thermal conductivity, K= 0.04 W/m.°K and thickness 0.16m is 10 W/m². The temperature of the inside wall is - 5°C. The outside wall temperature is

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Q. Thermal conductivity of a conducting solid material depends upon its

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Q. Pick out the wrong statement.

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Q. Shell side pressure drop in a shell and tube heat exchanger does not depend upon the

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Q. In the equation Q = UAΔt; Δt is

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Q. With increase in porosity, the thermal conductivity of a solid substance

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Q. For an ideal black body

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Q. In Joule's experiment, an insulated container contains 20 kg of water initially at 25°C. It is stirred by an agitator, which is made to turn by a slowly falling body weighing 40 kg through a height of 4 m. The process is repeated 500 times. The acceleration due to gravity is 9.8 ms⁻². Neglecting the heat capacity of agitator, the temperature of water (in °C) is

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Q. The Graetz number is concerned with the

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Q. Solid angle subtended by the finite surface at the radiating element is

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Q. Pick out the wrong statement.

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Q. In forced convection, the heat transfer depends on

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Q. With increase in temperature, the thermal conductivity of most liquids

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Q. What is the unit of thermal conductivity ?

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Q. The thermal radiation emitted by a body is proportional to Tⁿ, where T is its absolute temperature. The value of 'n' is exactly 4 for

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Q. It is not preferable to use superheated steam in evaporators, because of its very

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Q. It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is

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Q. LMTD for counterflow and prallel flow heat exchanger will be the same, when the

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Q. For large heat transfer area requirement, shell and tube heat exchanger is preferred, because it

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Q. Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heat flux vs. temperature drop for a boiling liquid, because

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