NATE CORE QUESTIONS WITH CORRECT ANSWERS GRADED TO PASS

1kwh of electric power is equivalent to ___ btu per hour. A. 3142 B. 6412 C. 9412 D. 6812 - A Gas valves operate at ____ voltage. A. 120v B. 230v C. 24v D. 12v - C What will be the resistance in the circuit if the supply voltage is 30v and current flowing through the circuit is 5A. A. 3 ohms B. 1/3 ohms C. 1/6 ohms D. 6 ohms - D Furnaces are placed into categories based upon. A. Venting characteristics B. Btuh capacity range C. Total airflow in CFM D. Gas valve type - A An oil separator is located in the____ A. Expansion line B. Liquid line C. Suction line D. Discharge line - D Propane and butane are ____ than air. A. Same weight B. Heavier C. Lighter - B Current in a closed circuit is limited by which of the following? A. Heat B. Voltage C. Temperature D. Resistance - D _____ use two special helical rotors that introduce suction vapors then compress them. A. All options are correct B. Scroll compressors C. Reciprocating compressors D. Screw compressors - D A high pressure steam boiler operates at a pressure greater than ____ A. 5 psig B. 15 psig C. 25 psig D 20 psig - B ____ is the heat that is absorbed or extracted when a substance changes its state. A. Enthalpy B. Entropy C. Latent heat D. Specific heat - C Sight glass is present at _____ in the refrigeration cycle. A. Liquid line B. Evaporation line C. Suction line D. Expansion valve - A When there is an increase in the heat load on the evaporator, the refrigerant will tend to evaporate at a _____ rate. A. Slower B. Faster - B The higher the ambient temperatures, ____ will be the evacuation time of the refrigerants from the system. A. Higher B. Lesser - B Which of the following shall not be used near flammable material. A. Halide leak detector B. Electronic leak detector C. Ultrasonic leak detector D. Sulfur leak detector - A The ____ of the manifold gauge set is used to charge, evacuate, add oil and recover refrigerant from a refrigeration and air conditioning system. A. Blue hose B. Yellow hose C. Red hose - B ____ is the temperature at which oil starts to produce a waxy substance that may interfere with the refrigeration system. A. Dash point B. Boiling point C. Flock point D. Pour point - C