NATE CORE REAL EXAM 200 QUESTIONS AND CORRECT ANSWERS{VERIFIED} 2024-2025 LATEST VERSION, Exams of Public Health

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NATE CORE REAL EXAM 200 QUESTIONS AND

CORRECT ANSWERS{VERIFIED} 2024- 2025

LATEST VERSION//ALREADY GRADED A+

d (very important) - ANSWER The ability to utilize all types of communication skills is ____ to the HVACR technician. a. not as important as "hands-on" technical skills b. somewhat important c. unimportant d. very important d (all of the above: clear, complete, concise) - ANSWER It is important to be ____ in filling out service orders so that office staff, other technicians, and customers will know what work you completed on the job. a. clear b. complete c. concise d. all of the above d (Refrigerant) - ANSWER When explaining to a customer that you have adjusted the system charge, which of the following terms is most appropriate? a. Freon b. Gas c. Juice d. Refrigerant

a (can help you diagnose the problem) - ANSWER Listening carefully to what a customer is telling you ____. a. can help you diagnose the problem b. is a waste of time c. is not necessary d. often will only confuse you b (listen to the customer first, then ask questions) - ANSWER When you arrive at a service call and meet the customer, you should ____. a. ask questions first, then listen to what the customer has to say b. listen to the customer first, then ask questions c. avoid discussion with the customer d. remind the customer that you are the professional and get on with your work b (1,600 ft3) - ANSWER What is the volume of a room that measures 10 ft by 20 ft with an 8-ft ceiling? a. 800 ft b. 1,600 ft c. 2,400 ft d. 3,200 ft b (1,200 CFM) - ANSWER What is the CFM requirements for an 1,800-ft2 house with 8-ft ceilings, if five air changes per hour are needed? a. 400 CFM b. 1,200 CFM c. 1,600 CFM

d. 2,400 CFM c (1,600 CFM) - ANSWER What is the CFM requirement for an 2,400-ft2 house with 8-ft ceilings, if five air changes per hour are needed? a. 400 CFM b. 1,200 CFM c. 1,600 CFM d. 2,400 CFM a (79 in2) - ANSWER What is the cross-sectional area of a 10-in round metal duct? a. 79 in b. 200 in c. 314 in d. 418 in Note: Area of a circle = π x radius^ d (1,800 ft/min) - ANSWER How fast does air with a velocity pressure of 0.20 in. w.g. move through a round duct? a. 400 ft/min b. 1,200 ft/min c. 1,600 ft/min d. 1,800 ft/min Note: Velocity = 4005 x (the square root of velocity pressure)

d (1,800 ft/min) - ANSWER How fast does air with a velocity pressure of 0.20 in w.g. move through a square duct? a. 400 ft/min b. 1,200 ft/min c. 1,600 ft/min d. 1,800 ft/min Note: Velocity = 4005 x (the square root of velocity pressure) d (all of the above: honest, loyal, patient) - ANSWER Customers depend on you to be ____. a. honest b. loyal c. patient d. all of the above c (demonstrate system operation and describe basic maintenance procedures to the customer) - ANSWER Before leaving a service call, you should be sure to ____. a. ask the customer for referrals b. collect payment in cash if possible c. demonstrate system operation and describe basic maintenance procedures to the customer d. try to sell the customer an equipment upgrade d (All of the above: it can cut hard or soft drawn copper; it leaves no metal shavings to contaminate the system; it produces a clean, square cut.) - ANSWER What is the advantage of using a tube cutter to cut copper pipe? a. It can cut hard or soft drawn copper

b. It leaves no metal shavings to contaminate the system c. It produces a clean, square cut d. All of the above a (soft drawn copper) - ANSWER Spring-type benders may be used on ____. a. soft drawn copper b. hard drawn copper c. all copper pipe d. steel pipe a (make a mechanical joint in tubing) - ANSWER A flaring tool is used to ____. a. make a mechanical joint in tubing b. measure pipe diameters c. remove burrs from piping d. solder tubing without the use of coupling d (solder tubing without the use of couplings) - ANSWER A swaging tool is used to ____. a. cut copper tubing b. make a mechanical joint in tubing c. remove burrs from piping d. solder tubing without the use of couplings a (It is very accurate) - ANSWER What is one of the advantages of a glass-stem thermometer? a. It is very accurate b. It is very durable

c. It comes with a digital readout d. Non of the above b (dry-bulb) - ANSWER In discussing human comfort, the temperature most commonly referred to is ____. a. dew point b. dry-bulb c. wet-bulb d. Fahrenheit d (wet-bulb) - ANSWER A sling psychrometer uses two glass-stem thermometers. One measures dry- bulb, and the other measures ____. a. dew point b. enthalpy c. relative humidity d. wet-bulb b (Bourdon tube) - ANSWER A standard refrigeration manifold uses what type of element to measure pressure? a. Bellows b. Bourdon tube c. Diaphragm d. Spring c (30 in. Hg to 350 psig) - ANSWER What is the pressure range of a standard compound gauge on a refrigerant manifold?

a. 0 to 350 psig b. 0 to 500 psig c. 30 in. Hg to 350 psig d. 30 in. Hg to 500 psig d (Vacuum pump) - ANSWER What is the best tool for removing moisture and non-condensibles from a system before adding refrigerant? a. Manifold gauge b. Micron analyzer c. Recovery machine d. Vacuum pump b (microns) - ANSWER A vacuum gauge reads pressure in ____. a. inches of mercury b. microns c. psia d. psig c (Micronic) - ANSWER Which of the following is not a method of leak detection? a. Soap bubbles b. Electronic c. Micronic d. Ultrasonic a (Recovery machine) - ANSWER To prevent the release of refrigerant to the atmosphere while removing it from a system, what type of equipment must be used?

a. Recovery machine b. Recycling machine c. Reclaim machine d. Vacuum pump b (air velocity) - ANSWER An anemometer uses a small fan blade to measure ____. a. air pressure b. air velocity c. air volume d. static pressure c (No flux is required) - ANSWER What is one of the advantages of using silver brazing rods for copper-to- copper joints? a. A lower melting temperature is required b. A propane torch is normally used c. No flux is required d. No nitrogen purge is needed d (all of the above) - ANSWER "Housekeeping" includes ____. a. disposal of waste b. fire prevention and protection c. proper storage of materials d. all of the above b (Goggles) - ANSWER What type of eye protection should you wear when drilling overhead?

a. Face shield b. Goggles c. Side shields d. Spectacles b (DOT) - ANSWER What agency regulates cylinders and chemicals transported in a service vehicle? a. ASHRAE b. DOT c. EPA d. OSHA a (contain information about personal protective equipment) - ANSWER Material safety data sheets ____. a. contain information about personal protective equipment b. do not provide recommendations regarding emergency procedures c. should be kept in a safe place off-site d. should be read after any chemical products have been used d (Never) - ANSWER When should oxygen be used in a refrigeration system? a. To clear a restriction in the line b. To pressurize for leak-testing c. To purge lines for brazing d. Never

c (Class A is an "ordinary" fire that involves the burning of wood, paper, or textile products, extinguishing agent: water. Class B is a fire that contains oil, grease, paint, varnish, or other chemicals, extinguishing agent: foam. Class C is an electrical fire, extinguishing agent: carbon dioxide.) - ANSWER Which of the following classifications of fire extinguishers should be used for electrical fires? a. A b. B c. C d. D d (All of the above: asphyxiating, flammable, toxic) - ANSWER Which of the following categories could be considered a hazardous atmosphere in a confined space? a. Asphyxiating b. Flammable c. Toxic d. All of the above a (Low oxygen level) - ANSWER Which of the following best describes an asphyxiating atmosphere? a. Low oxygen level b. Presence of ammonia c. Presence of carbon monoxide d. Presence of nitrogen c (5 ft) - ANSWER If a ladder is placed against a wall that is 20 ft tall, what is the proper distance away from the wall for the base of the ladder? a. 3 ft b. 4 ft

c. 5 ft d. 6 ft c (maintain three points of contact) - ANSWER When using a ladder, you should always ____. a. extend the ladder 18 in. above the roof line b. face away from the ladder c. maintain three points of contact d. straddle the space between the ladder and a nearby object a (Disconnect and lock out power before starting unless testing requires the power to be on) - ANSWER What is one of the most important safety precautions that you can take when working on electrical equipment? a. Disconnect and lock out power before starting unless testing requires the power to be on b. Keep one hand in your pocket while working on the power circuit c. Label all hot wires before starting d. Wear gloves suitable for high voltages a (When current travels through a ground path other than the neutral) - ANSWER When does a ground fault circuit interrupter open an electric circuit? a. When current travels through a ground path other than the neutral b. When the circuit is overloaded c. When there is a short circuit d. All of the above b (only by the person who installed the locks) - ANSWER Proper lockout/tagout procedures state that locks placed on a lockout device may be removed ____.

a. by anyone on the job site b. only by the person who installed the locks c. only after all fuses have been replaced d. only when the equipment is grounded c (evaporation) - ANSWER A natural cooling process produced by moisture on the skin changing to low- pressure steam is called ____. a. conduction b. convection c. evaporation d. radiation a (adding moisture) - ANSWER During the heating season, human comfort can be enhanced without changing the temperature of the air by ____. a. adding moisture b. reducing moisture c. increasing air filtration d. increasing air speed a (completely closed) - ANSWER During the cooling season, dampers on bypass humidifiers should be ____. a. completely closed b. completely open c. set at 25% d. set at 50% d (all of the above: liquid, solid, gas) - ANSWER All matter can exist as a ____.

a. liquid b. solid c. gas d. all of the above c (potential) - ANSWER Stored energy is called ____ energy. a. controlled b. kinetic c. potential d. quantum c (sensible) - ANSWER Heat that you can feel and measure directly with a thermometer is called ____ heat. a. absolute b. latent c. sensible d. super b (latent) - ANSWER The heat energy change associated with a phase (state) change is called ____ heat. a. absolute b. latent c. sensible d. super

d (specific) - ANSWER The amount of heat (Btu) needed to raise the temperate of 1 lb of a substance 1°F is called the ____ heat of the substance. a. absolute b. latent c. sensible d. specific b (liquid, solid) - ANSWER The latent heat of fusion is the amount of energy required to change 1 lb of a substance from the ____ phase to the ____ phase without changing its temperature. a. liquid, vapor b. liquid, solid c. solid, vapor d. vapor, liquid c (144 Btu) - ANSWER At 32°F, 1 lb of ice can be changed to 1 lb of water by adding ____ Btu. a. 32 Btu b. 44 Btu c. 144 Btu d. 970 Btu d (970 Btu) - ANSWER At 212°F, 1 lb of water can be changed to 1 lb of steam by adding ____ Btu. a. 32 Btu b. 44 Btu c. 144 Btu d. 970 Btu

a (saturated) - ANSWER When liquid and vapor phases of a substance exist together, and no more liquid can vaporize without more energy being added, the vapor is said to be ____. a. saturated b. stabilized c. subcooled d. superheated d (superheat) - ANSWER When a vapor is heated to a temperature higher than its saturation point, both the added heat and the temperature above saturation are called ____. a. latent heat b. sensible heat c. specific heat d. superheat b (evaporation) - ANSWER The process of molecules escaping from the surface of a liquid is called ____. a. condensation b. evaporation c. saturation d. subcooling c (sublimation) - ANSWER The process of a solid turning directly into a vapor without going through the liquid state is called ____. a. saturation b. subcooling c. sublimation

d. superheating b (kinetic) - ANSWER The continuous movement of molecules within a liquid or gas is called ____ energy. a. atomic b. kinetic c. potential d. stored a (latent, sensible) - ANSWER Enthalpy includes both ____ and ____ heat energy. a. latent, sensible b. latent, specific c. sensible, specific d. specific, absolute d (weight) - ANSWER The measurement of the force that gravity exerts is called ____. a. mass b. specific matter c. volume d. weight b (mass) - ANSWER The amount of matter in a substance is called ____. a. gravity b. mass c. volume d. weight

a (density) - ANSWER Weight per unit volume or mass per unit of volume is called ____. a. density b. specific gravity c. specific mass d. specific volume d (specific volume) - ANSWER Volume per unit of mass or weight is called ____. a. density b. specific gravity c. specific mass d. specific volume c (0.075 lb/ft3) - ANSWER Under standard conditions, air weighs approximately ____ lb/ft3. a. 0.055 lb/ft b. 0.065 lb/ft c. 0.075 lb/ft d. 0.085 lb/ft d (86°) - ANSWER Solve to find the Fahrenheit temperature corresponding to 30°C. a. 32° b. 68° c. 70° d. 86° Note: 32°F = 0°C. 9/5°F = 1°C.

°F = (9/5 x °C) + 32 °C = (°F - 32) x 5/ b (68°) - ANSWER Solve to find the Fahrenheit temperature corresponding to 20°C. a. 32° b. 68° c. 70° d. 86° Note: 32°F = 0°C. 9/5°F = 1°C. °F = (9/5 x °C) + 32 °C = (°F - 32) x 5/ d (26.7°C) - ANSWER Solve to find the Celsius temperature corresponding to 80°F. a. - 1.1°C b. 0.0°C c. 15.6°C d. 26.7°C Note: 32°F = 0°C. 9/5°F = 1°C. °F = (9/5 x °C) + 32 °C = (°F - 32) x 5/ c (15.6°C) - ANSWER Solve to find the Celsius temperature corresponding to 60°F. a. - 1.1°C b. 0.0°C

c. 15.6°C d. 26.7°C Note: 32°F = 0°C. 9/5°F = 1°C. °F = (9/5 x °C) + 32 °C = (°F - 32) x 5/ b (doubled) - ANSWER If the absolute temperature of a gas is doubled, under constant pressure the volume will be ____. a. cut in half b. doubled c. increased d. unchanged b (1.2 ft3) - ANSWER What is the new volume of 1 ft3 of air at 0°F when heated to 100°F? a. 1.0 ft b. 1.2 ft c. 2.0 ft d. 3.0 ft Note: Vf = Vi x (Tf / Ti) T = °F + 460 c (44.7 psia) - ANSWER If gauge pressure reads 30 psi, what is the corresponding absolute pressure?

a. 15.7 psia b. 34.7 psia c. 44.7 psia d. 60.7 psia c (Dalton's) - ANSWER The law that applies to the total pressure exerted by a mixture of gases or vapors is called ____ Law. a. Boyle's b. Charles' c. Dalton's d. Newton's d (6.28 x 10^18) - ANSWER A coulomb is a charge of ____ electrons. a. 6. b. 628 c. 628 Million d. 6.28 x 10^ b (electron flow) - ANSWER An ampere is a measurement of ____. a. electrical charge b. electron flow c. opposition to current d. potential energy b (force that moves electrons through a circuit) - ANSWER Voltage is best described as the ____.

a. amount of power being used in a circuit b. force that moves electrons through a circuit c. magnetic field surrounding a conductor d. resistance to the flow of electrons b (resistance) - ANSWER Current in a circuit is limited by ____. a. heat b. resistance c. temperature d. voltage a (conductor) - ANSWER A substance that permits the free movement of electrons is called a(n) ____. a. conductor b. insulator c. resistor d. semiconductor c (A short, large-diameter conductor) - ANSWER Which of the following conductors would have the least resistance? a. A long, large-diameter conductor b. A long, small-diameter conductor c. A short, large-diameter conductor d. A short, small-diameter conductor c (double) - ANSWER If the voltage in a circuit is doubled and the resistance remains the same, the current will ____.

a. drop to zero b. be cut in half c. double d. stay the same d (25 V) - ANSWER What is the voltage of a circuit if the resistance is 5Ω and the current is 5 A? a. 1 V b. 2.5 V c. 10 V d. 25 V a (2Ω) - ANSWER A circuit has a voltage of 10 V and a current of 5 A. What is the resistance? a. 2 Ω b. 15 Ω c. 20 Ω d. 50 Ω a (sum of all the resistances in the circuit) - ANSWER The total resistance of a series circuit is equal to the ____. a. sum of all the resistances in the circuit b. first resistance only c. last resistance only d. average of all the resistances in the circuit

c (the sum of the currents through the individual paths) - ANSWER The total current in a parallel circuit is ____. a. measured and divided by the number of circuit paths b. measured only at the first circuit path c. the sum of the currents through the individual paths d. the total of the first and last circuit paths c (power) - ANSWER The rate of doing work is called ____. a. amperage b. electricity c. power d. voltage c (1,000 W) - ANSWER One kilowatt is equal to ____. a. 10 W b. 100 W c. 1,000 W d. 10,000 W d (All of the above) - ANSWER Which of the following equations is used to solve for electric power? a. P = E x I b. P = I^2 x R c. P = E^2 / R d. All of the above

a (1 kW) - ANSWER What is the power in a circuit that has a current of 10 A and a resistance of 10Ω? a. 1 kW b. 10 kW c. 100 kW d. Cannot be determined by the information given c (the same as the voltage induced per turn of the primary coil) - ANSWER The voltage induced in each turn of the secondary coil of a transformer is ____. a. half the voltage induced per turn of the primary coil b. twice the voltage induced per turn of the primary coil c. the same as the voltage induced per turn of the primary coil d. determined by the ratio of turns in the primary coil to runs in the secondary coil c (volt-amperes) - ANSWER The load rating of a transformer is stated in ____. a. amperes b. volts c. volt-amperes d. watts d (stator, rotor) - ANSWER An ac induction motor consists of a stationary part called the ____ and a rotating part called the ____. a. field, armature b. primary winding, secondary winding c. start winding, run winding d. stator, rotor

a (1,200 RPM) - ANSWER What is the synchronous speed of a three-phase motor that has six poles and is operated on a 60-Hz alternating current? a. 1,200 RPM b. 3,600 RPM c. 4,320 RPM d. 7,200 RPM a (The lower the power factor, the less efficient the motor is) - ANSWER How does the power factor of an inductive motor affect efficiency? a. The lower the power factor, the less efficient the motor is b. The lower the power factor, the more efficient the motor is c. The higher the power factor, the less efficient the motor is d. The power factor has no effect on the efficiency of a motor c (Shaded-pole) - ANSWER Which of the following single-phase ac motors does not have a start winding? a. Capacitor-start, capacitor-run b. Permanent split-capacitor c. Shaded-pole d. Split-phase c (75 to 80%) - ANSWER A centrifugal switch opens the start winding circuit when a capacitor-start motor reaches approximately ____% of its full speed. a. 50 % b. 60 to 70% c. 75 to 80%