RAC & I.C. Engine - 2 - Mechanical Engineering MCQ

A refrigerator operates between the temperature of –23°C and 27°C. If one TR = 3.5 kW, the minimum power required per TR to operate the refrigerator is

In a vapour compression refrigeration plant, the refrigerant leaves the evaporator at 195 kJ/kg and the condenser at 65 kJ/kg. For 1 kg/s of refrigerant, the refrigeration effect is ___________ kW.

The wet bulb depression is zero, when relative humidity is equal to

The atmospheric air at 760 mm of Hg, dry bulb temperature 15°C and wet bulb temperature 11°C enters a heating coil whose temperature is 41°C. If the by-pass factor of the heating coil is 0.5, then what will be the dry bulb temperature of the air leaving the coil? 

Water at 42°C is sprayed into a stream of air at atmospheric pressure, dry bulb temperature of 40°C and a wet bulb temperature of 20°C. The air leaving the spray humidifier is not saturated. Which of the following statements is true?

During the adiabatic cooling of moist air

An air-conditioned room of volume 10 m³ has infiltration of air equivalent to 3 air changes per hour. Density of air is 1.2 kg/m³, specific heat C_p is 1 kJ/kgK and temperature difference between room and ambient air is 20 K. The sensible heat load due to infiltrated air is

In diesel engine, the suction consists of

In petrol engine, ignition takes place

The ratio of shaft horse power to the energy supplied by the fuel is called

Indicated horse power of a four-stroke engine is given by

The expression denotes the following efficiencies of an I.C. engine

The compression ratio for a diesel engine as compared to petrol engine is

A moist air sample has dry bulb temperature of 30°C and specific humidity of 11.5 g water vapour per kg dry air. Assume molecular weight of air as 28.93. If the saturation vapour pressure of water at 30°C is 4.24 kPa and the total pressure is 90 kPa, then the relative humidity (in %) of air sample is

Atmospheric air at 1.013 bar and 35°C has relative humidity 60%. The saturation pressure of water vapour at 35°C is 5.628 kPa. The specific humidity of water vapour in kg vapour per kg dry air will be

Moist air enters the cooling coil with mass flow rate of 10 kg-da/s at dry bulb temperature of 30°C and humidity ratio of 0.017 kg v/da. It leaves the cooling coil at dry bulb temperature of 16°C and humidity ratio of 0.008 kg v/da. If specific heat of humid air is 1.02 kJ/kg da K and latent heat of water vapour is 2500 kJ/kg v. The sensible and latent heat transfer of cooling coil are, respectively

In a sample of moist air at saturated atmospheric pressure of 101.325 kPa and 26°C the partial pressure of water vapour is 1.344 kPa. If the saturation pressure of water vapour is 3.36 kPa at 26°C, then what are the humidity ratio and relative humidity of moist air sample?