Topics: All categories in the pool
1: R-123 belongs to Group
- B-1
- A-3
- B-2
- B-3
2: Single compound Refrigerants are classified by what two criteria?
- Temperature range and hazardousness
- Flammability and temperature range
- Weight and color
- Flammability and toxicity
3: A thermometer inside a duct measures ____ heat.
- specific
- latent
- sensible
- hidden
4: Name a CFC refrigerant(s):
- R-11
- R-12
- R-123
- both a & b
5: Calculate the voltage in a series circuit when the total amperage is 10 amps and the resistors have values of: R1=12 ohms, R2=8 ohms, R3=4 ohms
- 2.40 volts
- 24.0 volts
- 2,400 volts
- 240 volts
6: What device measures the specific gravity of a substance?
- Thermometer
- Manometer
- Hydrometer
- Hygrometer
7: 1 Watt = ______ BTU's?
- 3.412
- 7.216
- 12
- 4.482
8: Megaohm meter's main function is
- to detect weak motor winding insulation of a refrigeration or air conditioning compressor by creating high DC voltages to the compressor
- to detect very high resistances to ground of refrigeration or air conditioning compressors
- to test very high value capacitors for large 3-phase refrigeration compressors and blower motors.
- Both a and b are correct
9: The measurement of heat in a particular substance is
- enthalpy
- specific heat
- sensible heat
- latent heat
10: A relief valve discharge capacity is rated in
- Pounds of air per minute.
- temperature minus pounds of air per second divided by release rate squared
- PSIA
- PSIG
11: At higher altitudes, the boiling point of refrigerant is
- higher
- the same
- equal to the coefficient of water at 32F
- lower
12: What is a Category "M" fluid?
- A typical refrigerant used on newer air conditioning and heat pump systems
- A fluid which is nonflammable, nontoxic, not damaging to human tissues, does not exceed 150 psig, and the designed temperature is between -20F to 366F
- Any fluid that exceeds 150 psig and has design temperatures over 366F
- A toxic fluid, which can produce serious irreversible harm to persons on breathing or bodily content
13: Halogenated refrigerants cannot be used with what material?
- Aluminum
- Copper
- Stainless steel
- Magnesium alloy
14: Volts x amps equals
- Inductance
- Impedance
- Ohms Law
- Watts
15: Which of the following is NOT a positive displacement compressor?
- centrifugal
- scroll
- reciprocating
- screw
16: A direct system
- is where the refrigerant comes in contact with the space refrigerated
- is a self-contained complete factory made and tested system
- is on where brine is cooled & circulated to the space refrigerated
- is one which encloses a separate body of evaporative refrigerant
17: The External equalizer of a TXV compensates for
- pressure drop across the condenser coil
- pressure within the evaporator
- pressure within the system
- pressure drop across the evaporator coil
18: By using nitrogen within a pipe during brazing operation,
- Copper oxide formation is prevented
- Exterior scale formation is minimized
- The explosion hazard is confined
- Discoloration is prevented
19: If a condenser is on a roof and the temperature is 35F and dropping the capacity
- doesn't change
- run as designed with low ambient controls
- increases
- decreases
20: The heat picked up in the evaporator must equal to
- the heat giving by the condenser
- the heat of compression
- the heat lost by the medium being cooled
- the heat gained by the condenser
21: "E" references ____ in the Ohm's law formula
- capacitance
- voltage
- amperage
- resistance
22: What device should be used on low-temperature freezers?
- discharge muffler
- oil separator
- hot-gas by-pass
- high capacity TXV
23: A mercury bulb controller is not recommended for
- low voltage use
- line or low voltage use
- use where vibration is severe
- line voltage use
24: The pressure relief device of a positive displacement compressor shall discharge in the ______________or in accordance with 9.7.8
- the liquid side of the system
- high side of the system
- low side of the system
- the vapor side of the system
25: Low pressure systems have what kind of compressor?
- Rotary
- Reciprocating
- Centrifugal
- Scroll