Q. Absorptivity and refletivity of a perfect black body are respectively

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Q. In thermal radiation for a black body (where, ε is emissivity and α is absorptivity)

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Q. Viscous & heat sensitive liquids are concentrated in __________ evaporators.

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Q. 1 BTU/hr.ft.°F is equal to __________ kcal/hr. m.°C.

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Q. Heat transfer by radiation between two bodies at T1 & T2 and in an ambient temperature of Ta°C depends on

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Q. The ratio of momentum diffusivity to thermal diffusivity is the __________ number.

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Q. For a perfectly transparent surface (like gases), the

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Q. Water is normally used as a coolant in the heat exchange equipments mainly because of its

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Q. The rate of emission of radiation by a body does not depend upon the

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Q. Which of the following has maximum thermal conductivity at the same temperature?

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Q. Maximum heat transfer rate is obtained in __________ flow.

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Q. In case of __________ boiling, the liquid temperature is below the saturation temperature and the boiling takes place in the vicinity of the heated surface.

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Q. The ratio of velocity head to tube side return loss in case of a multipass shell and tube heat exchanger is

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Q. Terminal point temperature differences between fluids in case of a heat exchanger is termed as

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Q. LMTD can't be used as such without a correction factor for the

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Q. Fqra cold viscous feed, backward feed gives __________ than forward feed.

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Q. Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer co-efficient is 3k/l. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade ?

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Q. The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are

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Q. Heat transfer rate described by Fourier's law will decrease, if the __________ increases.

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Q. A black body does not __________ radiation.

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