WorksheetsETAPA 4 (34-70)
Total questions: 37
Worksheet time: 37mins
Name
Class
Date
1.
Which metering device has the best ability to maintain constant evaporator pressure?
a)
Thermostatic Expansion Valve (TEV)
b)
Automatic Expansion Valve (AEV)
c)
Capillary Tube
d)
Fixed Orifice
2.
Which is NOT a result of a metering device being too restrictive?
a)
Head pressure will increase
b)
Suction pressure will decrease
c)
Superheat will increase
d)
Subcooling will decrease
3.
The external equalizer line on a TXV should be connected to:
a)
Evaporator outlet upstream sensing bulb
b)
Liquid line
c)
Evaporator inlet
d)
Evaporator outlet downstream sensing bulb
4.
A GFCI protects against:
a)
Appliance overloading
b)
Excess amperage & ground faults
c)
Short circuits
d)
Current flow to ground
5.
The resistance of an Negative Temperatures Coefficient (NTC) thermistor as temperature rises:
a)
Increases
b)
Decreases
c)
Remains same
d)
Fluctuates
6.
The resistance of a Positive Temperature Coefficient (PTC) thermistor as temperature rises:
a)
Increases
b)
Decreases
c)
Remains same
d)
Fluctuates
7.
Total resistance in a simple series circuit is:
a)
Sum of resistances
b)
Same as parallel
c)
No
d)
DC only
8.
If current flow increases, magnetic field around conductor:
a)
Increases
b)
Decreases
c)
Fluctuates
d)
Remains same
9.
Symbol for electrical impedance:
a)
R
b)
I
c)
P
d)
Z
10.
If 100W and 30W bulbs are in series, which is brighter?
a)
100W bulb
b)
30W bulb
c)
Both equal
d)
Neither lights
11.
Total resistance in a parallel circuit is:
a)
Sum of resistances
b)
Equal to lowest branch
c)
Less than any branch
d)
Highest branch value
12.
Direct result of current flow through a straight wire:
a)
Creates magnetic field
b)
Becomes inductive load
c)
Electrons lose charge
d)
Wire becomes capacitive
13.
In a parallel circuit total current equals:
a)
Same in all loads
b)
Sum of all branch currents
c)
Voltage drop same
d)
Sum of voltage drops
14.
In a parallel circuit voltage drop across loads:
a)
Same across all loads
b)
Equal in all loads
c)
Different
d)
Sum of all drops
15.
Total capacitance in parallel is:
a)
Sum of individual capacitances
b)
Sum of inverses
c)
Lower than smallest
d)
Both B & C
16.
Total capacitance in series is:
a)
Sum
b)
Sum of inverses
c)
Lower than smallest
d)
Both B & C
17.
Safety devices are connected:
a)
Parallel with load
b)
Parallel with sensing device
c)
Series with load
d)
Series with sensing device
18.
A typical residential gas furnace requires:
a)
Double pole 15A
b)
Single pole 15A
c)
Double pole 20A
d)
Single pole 20A
19.
Transformers with lower secondary voltage are:
a)
Step up transformers
b)
Step down transformers
c)
Autotransformers
d)
Both B & C
20.
Electrostatic theory suggests:
a)
Electrons attract each other
b)
Protons attract each other
c)
Electrons attract protons
d)
Electrons neutrally charged
21.
Unit of ELECTROMOTIVE (EMF) is:
a)
Ohms
b)
Amps
c)
Volts
d)
µF
22.
Two dissimilar metal wires joined are called:
a)
Thermocouple
b)
Bimetal strip
c)
RTD
d)
Thermistor
23.
Energizing the coil moves an armature opening fluid passage in a:
a)
High-pressure control
b)
Discharge service valve
c)
Suction service valve
d)
Solenoid valve
24.
Transformers are rated in:
a)
Watts
b)
Volt-Amperes (VA)
c)
Amps
d)
Ohms
25.
If ΔT increases, heat transfer rate will:
a)
Increase
b)
Decrease
c)
Stay the same
d)
Independent of ΔT
26.
Low voltage per Canadian Electrical Code (CEC) is clasiffied as:
a)
31–750V
b)
0–1000V
c)
0–750V
d)
120–1000V
27.
NO cooling: 24V at contactor coil, 240V at line, 0V at load, fan draws 1.5Ω. Problem:
a)
Burned compressor
b)
Thermostat not calling
c)
Contactor defective
d)
Unit shorted to ground
28.
Insufficient cooling: outdoor fan slow, compressor OK, run capacitor reads 0µF:
a)
Loose wires
b)
Fan shaft tight
c)
Fan winding shorted
d)
Fan run capacitor bad
29.
NO cooling: 240V line, 0V R→Y, 0V transformer secondary, 0V coil:
a)
Contactor failed
b)
Thermostat failed
c)
Transformer failed
d)
Breaker tripped
30.
G terminal on furnace board is used to control:
a)
Condensing unit
b)
Blower motor
c)
Gas valve
d)
Power to thermostat
31.
R terminal on furnace board supplies:
a)
Condensing unit
b)
Blower
c)
Gas valve
d)
Power to thermostat
32.
W terminal used to control:
a)
Condensing unit
b)
Blower
c)
Gas valve
d)
Power thermostat
33.
Y terminal used to control:
a)
Condensing unit
b)
Blower
c)
Gas valve
d)
Power thermostat
34.
Reading full supply voltage across a contact means the contact is:
a)
Open
b)
Closed
c)
Depends
d)
Either
35.
Reading 0 volts across a contact means it is:
a)
Open
b)
Closed
c)
Circuit energized
d)
De-energized
36.
Incorrect ohmmeter statement:
a)
Measures DC circuits
b)
Measures AC circuits
c)
Measures load while energized
d)
Measures accurately de-energized
37.
Replacement for 35µF 440V run capacitor is:
a)
20 + 20 µF 440/370V
b)
20 + 15 µF 440/370V
c)
20 + 12.5 µF 440/570V
d)
20 + 15 µF 370/570V
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