Flashcards in HVAC Deck (257)
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1
What type of charge does an electron have?
A. positive
B. Negeative
C. Neutral
D. Negative- positive
B
2
If five electrons combine with three protons, the net charge will be
A. negative
B. positive
C. zero
D. neutral
A
3
what part of an atom moves from one atom to another?
A. proton
B. Neutron
C. electron
D. molecule
C
4
Typical insulations are
A. copper, silver, gold
B. steel, bronze, brass
C. glass, rubber, plastic
D. aluminum, nickel, magnesium
C
5
The ampere is
A. the difference in potential between two charges
B. a measure of the quantity of electrons flowing past a point in the ectrical circuit in a given time
C. the unit of measure for resistance
D. the unit of measure for capacitance
B
6
If two light bulbs are wired in series and one bulb burns out, the other bulb will
A. go out
B. stay on
C. stay on, but it will be dimmer
D. stay on, but it will be brighter
A
7
what happens to the currnt in a circuit if the resistance is increased
A. the current remains the same
B . the current increases
C. the current decreases
D. this cannot be determined
c
7
what happens to the currnt in a circuit if the resistance is increased
A. the current remains the same
B . the current increases
C. the current decreases
D. this cannot be determined
c
8
An element in an electric heating unit is connected to a 232-V power supply. The current flow through the element is 19 A. What is the resistance of the element?
A. 8
B.10
C.12
D.14
c
9
As loads are added ina parrallel circuit, the total resistance of the circuit.
A. will increase
B. will decrease
C. will remain the same
D. cannot be determined
B
10
To find the watts of electrical power in an electrical ciriuit, you multiply _____ together.
A. ohms and amperes
B. ohms and volts
C. volts and amperes
D. volts, amperes, and ohms
C
11
If a conductor carrying electrical current is formed into a coil, the magnetic field around the wire will.
A. cancel out
B. increase
C. decrease
D. remain the same
B
12
T/F Ohmmeters are to be used only on circuits that are de-energized.
T
13
T/F In a circuit with two or more ressistance in series, the total resistance in the circuit is the sum of the resistance.
T
14
T/F IF three bulbs are wired in parrallel and one bulb burns out, the total current of the circuit will decrease.
T
15
T/F In a circuit with two or more resistance in parallel, the total resistance in the circuit is the sum of the resistance in the circuit.
F
16
T/F When calculating the total resistance of a parallel circuit, the result will always be lower than the lowest resistance.
T
17
T/F One kilowatt of electrical energy is equal to 1,000,000 watts.
F
18
T/F IF a conductor carrying electrical current is formed into a coil, the strength of the magnetic field generated by the wire wil increase.
T
19
T/F The unit of measurement for the charge a capacitor can store is called a Joule.
F
20
T/ F As the diameter of a wire increases, its resistance will also increase.
F
21
T/F Copper wire size are measured in circular mills.
T
22
T/F The main purpose of a rectifier is to convert direct current (DC) to alternating current (AC).
F
23
T/F A PTC thermistor causes the resistance of the thermistor to increase when its temperture rises.
T
24
T/F A single diode can be connected as a full wave rectifier.
F
25
T/F When checking a diode with an ohmmneter and the meter shows a resistance, if the merer leads are reversed, it should show infinity.
T
26
T/F A heat sink is a device to improve the purity of the electrons in an electrical circuit.
F
27
A good conductor of electricty has few ___________ electrons, which cna move easily from one atom to another.
Valence
28
The unit of meausure for the current flow of electrical energery is the
__________.
Ampere
29