Font size
WorksheetsFinal Exam
Total questions: 38
Worksheet time: 32mins
What is current flow?
Flow of voltage in a circuit.
Impedance of a circuit.
Inductive reactance of the circuit.
Flow of electrons in the circuit.
What is impedance?
Opposition to alternating current flow.
Electrical pressure.
Amperage.
Voltage applied to the circuit.
Any material that will readily release electrons is called
an insulator.
a conductor.
a resistance.
a neutron.
The symbol for current is
E
I
R
W
A Technician is running three# 10 THNN conductors from the disconnect to a condensing unit, using one red, one black and one green wire. Which color is used for the ground?
red
black
green
white
An electron has
no charge
a negative charge
a positive charge
extra electrons
What is resistance?
Opposition to current flow
Electrical pressure
Amperage
Voltage applied to the circuit
In electrical wiring a black colored wire usually indicates the;
safety ground.
neutral conductor
ground conductor.
hot conductor.
Two 20 Ohm resistors are wired in series, the total resistance of the circuit is;
80 Ohms
40 Ohms
20 Ohms
10 Ohms
What term is used to describe the output side of a transformer?
Low inductive side.
High inductive side.
Primary side.
Secondary side.
Which of the following statements about current is true?
Current flow is the same as voltage.
Current flow will increase when voltage increases.
Current flow will increase when resistance increases.
Current flow will decrease when voltage increases.
Which of the following is the correct formula for determining wattage in an electrical circuit?
W=E×I
W = E/ R
W=I/R
W= E×R
Three resistors are wired in parallel. Two of the resistors have a value of 12 ohms, one resistor has a value of 6 ohms. What is the total resistance of the circuit?
30 ohms
18 ohms
3 ohms
It is not possible to wire resistors of different values in parallel.
This type of drawing illustrates where the components are located on the appliance.
pictorial
schematic
ladder diagram
outside
Heat which causes a change in temperature of a substance is called;
latent heat.
sensible heat.
superheat.
regular heat.
Heat which causes a change in state of a material without a change in temperature is;
latent heat.
sensible heat.
superheat.
regular heat.
A refrigerant gives up heat when;
it condenses.
it evaporates.
it is compressed.
it vaporizes.
The state of the refrigerant in the suction line should be;
high pressure/ high temperature liquid.
high pressure/ low temperature vapor.
low pressure/ low temperature liquid.
low pressure/ low temperature vapor.
The evaporator;
transfers heat from the refrigerated space to the refrigerant.
transfers heat from the refrigerant to the refrigerated space.
transfers heat from the refrigerant to the ambient air.
transfers heat from the ambient air to the refrigerated space.
Pressures lower than atmospheric are measured in;
Inch lbs.
micrograms
psig
microns.
Conduction, convection and radiation are the;
units of Btu's needed to cause change of state.
results from a liquid being substantially subcooled.
results after a liquid has been compressed.
three methods by which heat can travel.
A compound gauge measures;
pressure and vacuum.
pressure and temperature.
pressure and humidity.
wet and dry bulb temperatures.
The main function of the condenser is to:
store liquid refrigerant.
remove heat from the refrigerant.
remove moisture from the refrigerant.
add heat to the refrigerant.
The standard unit for measuring the quantity of heat in a substance is:
degrees Fahrenheit.
degrees Celsius.
degrees Rankin.
the British Thermal Unit (Btu).
Hard type solder or brazing rods used for Refrigeration/Air Conditioning installation and repairs have a flow point of approximately;
1100 to 1400° F
900 to 1000° F
600 to 900° F
300 to 600° F
Which of the following must be present for combustion to occur?
Nitrogen and Oxygen in air
Fuel, Hydrogen and Ignition
H2O, Fuel and Ignition
Air, fuel and Ignition
The chemical name for natural gas is:
Methane.
Propane.
Butane.
Octane.
A gas furnace has an inducer draft fan. The thermostat has called for heat. The ignition sequence begins with the proper operation of the;
fan limit switch.
dilution air switch.
rollout switch.
air pressure switch.
A BTU is the amount of heat required to raise the temperature of one pound of water:
one degree Centigrade.
one degree Fahrenheit.
one degree Celsius.
one degree Kelvin.
The minimum pitch for gas pipe toward the service meter is;
1" per 15' run.
1/2" per 15' run.
1/3" per 15' run.
1/4" per 15' run.
Pipe joint compound should be applied to:
male threads completely.
male threads less two end threads.
both male and female threads.
female threads.
The proper name of the tool used to cut the threads of a steel pipe is a:
pipe cutter.
tap.
ratchet head cutter.
die.
A technician connects the electrical circuit to an 80,000 BTU gas furnace with a 3-ton cooling system. The fan motor is rated 1/3 HP@120 VAC. What size conductor would normally be used? (copper conductors)
8--10 AWG
12-14AWG
16-18AWG
20-22AWG
The states of refrigerant as it enters and exits the compressor are:
superheated liquid
low pressure, subcooled vapor
low pressure, superheated vapor
low pressure, superheated vapor
What is an ECM type motor?
Efficient capacitor motor.
Electronic commutated motor.
Electrical conductive motor.
Electronic current motor.
According to the picture, what type of compressor motor is used in the package unit?
Shaded Pole.
Induction Start.
CRS.
PSC.
Label the 4 components of the refrigeration cycle.
metering device
evaporator
condenser
compressor
What does HVAC stand for?
H
Heating
V
Ventilation
A
Air
C
Conditioning
