問題一覧
1
Electrostatic fields are also known as
Dielectric field
2
The presence of any small amount of potassium carbonate deposits on the top of nickel-cadmium battery cells in service is an indication of
Normal operation
3
A 14-ohm resistor is to be installed in a series circuit carrying .05 ampere. How much power will the resistor be required to dissipate?
At least 35 milliwatts
4
What is the total capacitance of a certain circuit containing three capacitors with capacitance with capacitances of .25 microfarad, .03 microfarad, and .12 microfarad, respectively? (Note: C(T)= C(1) + C(2) + C(3))
4 μF
5
A thermal switch, or thermal protector, as used in an electric motor, is designed to
Open the circuit in order to allow cooling of the motor
6
During discharge, nickel-cadmium batteries will show a lower liquid level than when at full charge because
The electrolytes become absorbed into the plates
7
The voltage drop in a circuit of known resistance is dependent on
The amperage of the circuit
8
When referencing resistance in a parallel DC circuit, which of the following statements is true?
The total current is equal to the sum of the currents through the individual branches of the circuit
9
What is the basic unit of electrical quantity?
Coulomb
10
A fully charge lead-acid battery will not freeze until extremely low temperatures are reached because
Most of the acid is in the solution
11
Which of the following is commonly used as a rectifier in electrical circuits?
Diodes
12
The electrolyte of a nickel-cadmium battery is the lowest when the battery is
In a discharged condition
13
If three resistors of 3 ohms, 5 ohms, and 22 ohms are connected in series in a 28-volt circuit, how much current will flow through the 3-ohm resistor?
0.93 ampere
14
What is the opposition to the flow of the AC produced by a magnetic field with generated back voltage (EMF) called?
Inductive reactance
15
Typical application for Zener diodes is as
Voltage regulators
16
What will a voltmeter read if properly connected across a closed switch in a circuit with electrical power on?
Zero voltage
17
Convert farads to picofarads by:
Multiplying farads by 10 to the power of 12
18
When charging current is applied to a nickel-cadmium battery, the cells emit gas
Toward the end of the charging cycle
19
A circuit has an applied voltage of 30 volts and a load consisting of a 10-ohm resistor in series with a 20-ohm resistor. What is the voltage drop across the 10-ohm resistor?
10 volts
20
What may result if water is added to a nickel-cadmium battery when it is not fully charged?
Excessive spewing is likely to occur during the charging cycle
21
The amount of electricity a capacitor can store is directly proportional to the
Plate area and inversely proportional to the distance between the plates.
22
The potential difference between two conductors which are insulated from each other is measured in
Volts
23
When inductors are connected in series in a circuit, the total inductance is (where the magnetic fields of each inductor do not affect the others). (Note: L(T) = L(1) + L(2) + L(3)...)
Equal to the sum of the individual inductances
24
Which term means .001 ampere?
Milliampere
25
Transfer of electric energy from one circuit to another without the aid of electrical connections
Is called induction
26
Which effect does not apply to the movement of electrons flowing in a conductor?
Static energy
27
What unit is used to express electrical power?
Watt
28
The term that describes the combined resistive forces in an ac circuit is
Impedance
29
Which of the following logic gates will provide an active high out only when all inputs are different?
XOR
30
How many amperes will a 28-volt generator be required to supply to a circuit containing five lamps in parallel, three of which have a resistance of 6 ohms each and two of which have a resistance of 5 ohms each?
25.23 amperes
31
A 24-volt source is required to furnish 48 watts to a parallel circuit consisting of four resistors of equal value. What is the voltage drop across each resistor?
24 volts
32
An increase in which of the following factors will cause an increase in the inductive reactance of a circuit?
Inductance and frequency
33
In a P-N-P transistor application, the solid state device is turned on when the
Base is negative with respect to the emitter
34
Convert farads to microfarads by
Multiplying farads by 10 to the power of 6
35
When calculating power in a reactive or inductive ac circuit, the true power is
Less than the apparent power
36
How can the state-of-charge of a nickel- cadmium battery be determined?
By a measured discharge
37
A lead-acid battery with 12 cells connected in series (no-load voltage = 2.1 volts per cell) furnishes 10 amperes to a load of 2- ohms resistance. The internal resistance of the battery in this instance is
0.52 ohms
38
The purpose of providing a space underneath the plates in a lead acid battery’s cell container is to
Prevent sediment buildup from contacting the plates and causing a short circuit
39
In a parallel circuit with three 6-ohm resistors across a 12-volt battery, what is the total current (lt) value in the circuit?
6 amps
40
Which statement regarding the hydrometer reading of a lead-acid storage battery electrolyte is true?
The hydrometer reading does not require a temperature correction if the electrolyte temperature is 80°F
41
The end-of-charge voltage of a 19-cell nickel-cadmium battery, measured while still on charge,
Depends upon its temperature and the method used for charging
42
Which is correct concerning a parallel circuit?
Total resistance will be smaller than the smallest resistor
43
Which of these will cause the resistance of a conductor to decrease?
Decrease the length or increase the cross-sectional area
44
What does the letter Q symbolize when measuring electrical charge?
Coulomb
45
Which condition is an indication of improperly torqued cell link connections of a nickel-cadmium battery?
Heat or burn marks on the hardware
46
The working voltage of a capacitor in an ac circuit should be
At least 50% greater than the highest applied voltage
47
The electrolyte of a nickel cadmium battery is highest when the battery is
In fully charged condition
48
The opposition offered by a coil to the flow of alternating current is called (disregard resistance)
Inductive reactance
49
Capacitors are sometimes used in dc circuits to
Smooth out slight pulsations in current/voltage
50
Which of the following best describes the contributing factors to thermal runaway in a nickel-cadmium battery installed in an aircraft?
Low internal resistance intensified by high cell temperatures and a high current discharge/charge rate in a constant potential (voltage) charging system
51
Which is correct in reference to electrical resistance?
If one of three bulbs in a parallel lighting circuit is removed, the total resistance of the circuit will become together
52
When referring to an electrical circuit diagram, what point is considered to be at zero voltage?
The ground reference
53
What factors strengthen a coil inductor?
Adding coils close together
54
A cabin entry light of 10 watts and a dome light of 20 watts are connected in parallel to a circuit 30-volt source. If the voltage across the 10-watt light is measured, it will be
Equal to the voltage across the 20-watt light
55
The correct way to connect a test voltmeter in a circuit is
In parallel with a unit
56
002KV equals
2.0 volts
57
The method used to rapidly charge a nickel- cadmium battery utilizes
Constant voltage and varying current
58
If each cell, connected in series, equals 2 volts, how would a 12-cell lead acid battery be rated?
24 volts
59
Through which material will magnetic lines of force pass the most readily?
Iron
60
The basis for transformer operations in the use of alternating current is mutual
Inductance
61
In an ac circuit, the effective voltage is
Less than the maximum instantaneous voltage.
62
Which of the following statements is/are generally true regarding the charging of several aircraft batteries together? 1. Batteries of different voltages (but similar capacities) can be connected in series with each other across the charger, and charged using the constant current method. 2. Batteries of different ampere-hour capacity and same voltage can be connected in parallel with each other across the charger, and charged using the constant voltage method. 3. Batteries of the same voltage and same ampere-hour capacity must be connected in series with each other across the charger, and charged using the constant current method.
1 and 2
63
What is the purpose of the ground symbol used in electrical circuit diagrams?
To show that there is a return path for the current between the source of electrical energy and the load
64
In nickel-cadmium batteries, a rise in cell temperature
Causes a decrease in internal resistance
65
Forward biasing of a solid state device will cause the device to
Conduct
66
Which of the following best describes the operating principle in a nickel-cadmium battery installed in an aircraft?
To completely charge a nickel-cadmium battery, some gassing must take place; thus, some water will be used
67
Which requires the most electrical power? (Note: 1 hp = 746 watts)
A 1/5 horsepower, 24-volt motor which is 75 percent efficient
68
A 1-horsepower , 2-volt dc electric motor that is 80 percent efficient requires 932.5 watts. How much power will a 1- horspeower, 12-volt dc electric motor that is 75 percent efficient require? (Note: 1hp= 746 watts)
994.6 watts
69
A 12-volt electric motor has 1,000 watts input and 1 hp output, Maintaining the same efficiency, how much input power will a 24-volt, 1 hp electric motor require? (Note: 1hp = 746 watts)
1,000 watts
70
Unless otherwise specified, any values given for current or voltage in an ac circuit are assumed to be
Effective values
71
What is the likely result of servicing and charging nickel-cadmium and lead acid batteries together in the same service area?
Contamination of both types of batteries
72
When different rated capacitors are connected in parallel in a circuit, the total capacitance is (Note: C(T) = C(1) + C(2) + C(3)...)
Equal to the sum of all the capacitances
73
What determines the amount of current which will flow through a battery while it is being charged by a constant voltage source?
The state-of-charge of the battery
74
What is the operating resistance of a 30- watt light bulb designed for a 28-volt system?
26 ohms
75
What is the total capacitance of a circuit containing three capacitors in parallel with capacitances of .02 microfarad, .05 microfarad, and .10 microfarad, respectively?
0.170 μF
76
If electrolyte from a lead-acid battery is spilled in the battery compartment, which procedure should be followed?
Apply sodium bicarbonate solution to the affected area followed by a water rinse
77
In an N-P-N transistor application, the solid state device is turned on when the
Base is positive with respect to the emitter
78
Which requires the most electrical power during operation? (Note: 1hp = 746 watts)
Two lights requiring 3 amperes each in a 24-volt parallel system
79
In a parallel circuit with four 6-ohm resistors across a 24-volt battery, what is the total voltage across resistor-three (VR3) in the circuit?
24 volts
80
What happens to the current in a voltage step-up transformer with a ratio of 1 to 4?
The current is stepped down by a 1 to 4 ratio