Q. An electric cable of aluminium conductor (k = 240 W/mK) is to be insulated with rubber (k = 0.15 W/mK). The cable is to be located in air (h = 6 W/m²). The critical thickness of insulation will be

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Q. A cube at high temperature is immersed in a constant temperature bath. It loses heat from its top, bottom and side surfaces with heat transfer coefficients of h1, h2 and h3 respectively. The average heat transfer coefficient for the cube is

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Q. The dehumidification process, on the psychrometric chart, is shown by

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Q. The vertical and uniformly spaced lines on a psychrometric chart indicates

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Q. A furnace is made of a red brick wall of thickness 0.5 m and conductivity 0.7 W/mK. For the same heat loss and temperature drop, this can be replaced by a layer of diatomite earth of conductivity 0.14 W/mK and thickness

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Q. In a refrigeration system, the expansion device is connected between the

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Q. The heat rejection factor (HRF) is given by

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Q. Wein's law states that the wave length corresponding to __________ is proportional to the absolute temperature.

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Q. In a domestic vapour compression refrigerator, the refrigerant commonly used is

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Q. In case of sensible heating of air, the coil efficiency is given by (where B.P.F. = By-pass factor)

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Q. The coefficient of performance (C.O.P.) is the reciprocal of the efficiency of a heat engine.

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Q. The wet bulb temperature at 100% relative humidity is __________ dry bulb temperature.

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Q. The freezing point of sulphur dioxide is

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Q. The ratio of the energy absorbed by the body to the total energy falling on it, is called

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Q. In order to cool and dehumidify a stream of moist air, it must be passed over the coil at a temperature

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Q. The coefficient of performance of vapour compression refrigeration system is quite __________ as compared to air refrigeration system.

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Q. In order to collect liquid refrigerant and to prevent it from going to a __________ , a device known as accumulator is used at the suction of compressor.

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Q. Which of the following refrigerant has the lowest boiling point?

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Q. During sensible cooling of air, the relative humidity increases.

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Q. Sensible heat factor is given by (where S.H. = Sensible heat, and L.H. = Latent heat)

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