NATE CORE STUDY GUIDE QUESTIONS WITH ANSWERS VERIFIED CORECT

Which of the following is not the product of incomplete combustion: - Oxides of nitrogen An oil trap is required at the base of the discharge line of the vertical riser is _____ or above - 8 feet A diode allows current to flow in one direction: - True 1 Watt = _____ Btu - 3.41 Current in a closed circuit is limited by which of the following: - resistance An oil separator is located in the _____: - Discharge line ______ is the heat that is absorbed or extracted when a substance changes its state: - Latent heat _______ is the temperature at which oil starts to produce a waxy substance that may interfere with the refrigeration system: - Floc Point 1 kWh of electric power is equivalent to ______ Btu per hour: - 3412 What will be the resistance in the circuit if the supply voltage is 30V and current flowing through the circuit is 5A: - 6 OHM Gas valves operate at _____ voltage: - 24V _______ use two special helical rotors that introduce suction vapors then compress them: - Screw Compressor A high pressure steam boiler operates at a pressure greater than ______ : - 15 PSIG In Fire tube boiler, which of the following pass through the tubes: - Flue Gas 1 kilo watt = ______ Btu - 3140 BTU Turning the TXV valve stem in _______ direction increases super heat: - Clockwise Which of the following compressor uses pistons, cylinders and valves to compress the refrigerant gas: - Reciprocating Compressor Most of the heat transfer from the heat exchanger is by which of the following: - Convection Relays and contactors are ____ control switches: - Electrically Operated Which of the following law states that the total pressure of a confined mixture of gases is the sum of pressures of each of the gases in the mixture: - Daltons Law At 32°F, 1 lb of ice can be changed to 1 lb of water by adding ____ Btu - 144 BTU Which of the following circuit does not have multiple paths for current flow: - series Dual voltage three phase motor has _____ number of terminals - 9 Which one of the following is known as the line that connects between the metering device and the evaporator: - Inlet line Approximately _____ voltage is required for creating a spark on a spark ignition system: - 15,000V Which one of the following in the refrigeration cycle changes the refrigerant from low pressure gas to high pressure gas: - Compressor Heat transfer that takes place in liquids and gases in which of the following: - Convection Which of the following is used to measure the pressure drop across the air filter: - Manometer What will be typical range of the current sensor: - 4-20 mA RTD which measure temperature have a positive temperature coefficient: - True ______ temperature is the temperature is the temperature below which moisture condense out of air - Dew Bulb Curved boundary In Psychrometric chart indicates which of the following: - Dew point temperature line _____ is a combination of both sensible heat and latent heat: - Enthalpy The heat energy change that is associated with a change in the phase (state) is: - Latent Heat In water-tube boilers, pressures range from ______ : - 50 to 5,000 psig Which one of the following is used in systems for pressurizing the building: - Exhaust or relief dampers The temperature-resistance characteristic of a thermistor is _________ : - Non linear At _________ this superheated refrigerant vapor pressure and temperature is added: - Compressor For every 1000 feet above sea level,the capacity of a natural gas furnace is de-rated by _______ - 4% If the surrounding air is colder than the skin temperature, the body gains heat: - False The power developed by the centrifugal pump is proportional to _________ its speed: - CUBE