Q. The rato of energy transferred by convection to that by conduction is called

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Q. A refrigerating system operating on reversed Brayton refrigeration cycle is used for maintaining 250 K. If the temperature at the end of constant pressure cooling is 300 K and rise in the temperature of air in the refrigerator is 50 K, then the net work of compression will be (assume air as working substance with cp = 1 kJ/kg)

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Q. Wet bulb temperature indicates the moisture content in air.

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Q. A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100° C and leaves at 60° C. A cold fluid enters the heat exchanger at 40° C. The mean temperature difference between the two fluids is

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Q. The inclined and non-uniformly spaced straight lines on a psychrometric chart indicates wet bulb temperature.

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Q. In a psychrometric chart, dew point temperature lines are horizontal and non-uniformly spaced.

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Q. If the evaporator temperature is kept constant, the coefficient of performance of a refrigeration cycle __________ with the increase in condenser temperature.

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Q. The by-pass factor, in case of sensible cooling of air, is given by (where td1 = Dry bulb temperature of air entering the cooling coil, td2 = Dry bulb temperature of air leaving the cooling coil, and td3 = Dry bulb temperature of the cooling coil)

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Q. The evaporator used in house-hold refrigerators is

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Q. The drier in a refrigeration system removes moisture in the system.

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Q. When the discharge pressure is too high in a refrigeration system, high pressure control is installed to stop the compressor.

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Q. A grey body is one whose absorptivity does not vary with temperature and wave length of the incident ray.

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Q. The wet bulb temperature during sensible cooling of air

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Q. In absorption vapour systems, the refrigerant widely used is R-12.

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Q. Hydrogen is used in electrolux refrigeration system so as to __________ the rate of evaporation of the liquid ammonia passing through the evaporator.

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Q. Dry bulb temperature is the temperature of air recorded by a thermometer, when

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Q. In a spray washing system, if the temperature of water is higher than the dry bulb temperature of entering air, then the air is

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Q. A valve which maintains a constant degree of superheat at the end of the evaporator coil, is called

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Q. The atmospheric air at dry bulb temperature of 15°C enters a heating coil maintained at 40°C. The air leaves the heating coil at 25°C. The by-pass factor of the heating coil is

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Q. An infinite parallel planes with emissivities e1 and e2, the interchange factor for radiation from surface 1 to surface 2 is given by

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