NAVEDTRA 14173A NEETS MODULE 1 CHAPTER 1 Flashcards
(167 cards)
1
Q
Matter can be found in which of the following forms?
A
- Solid
- Liquid
- Gaseous
- EACH OF THE ABOVE
2
Q
A substance that CANNOT be reduced to a simpler substance by chemical means is called a/an
A
- element
3
Q
A molecule is the smallest possible particle that retains the characteristic of which of the following substances?
A
- A compound
4
Q
An atom is the smallest possible particle that retains the characteristic of which of the following substances?
A
- An element
5
Q
What subatomic particle has a negative charge and a small mass?
A
- Electron
6
Q
What subatomic particle has a positive charge and a large mass?
A
- Proton
7
Q
What subatomic particle has no charge?
A
- Neutron
8
Q
When light is represented as a tiny packet of energy, what are these packets of energy called?
A
- Photons
9
Q
If light energy collides with an orbiting electron, what happens to the electron?
A
The electron will jump to an orbit further from the nucleus
10
Q
After the action described in question 1-9 occurs, the electron will return to the condition it had before being acted upon by the light. When the electron returns to this condition, which of the following actions occurs?
A
The valence of the atom changes
11
Q
The number of electrons in the outermost shell of an atom determines which of the following characteristics of the atom?
A
- Valence
12
Q
When an atom gains or loses an electron, which of the following terms applies?
A
Ionized
13
Q
What is the main difference between conductors, semiconductors, and insulators?
A
The number of free electrons
14
Q
A substance with an excess of electrons is considered to be in what electrical state?
A
Negative
15
Q
Which of following actions describes the easiest way to accumulate a static electric charge?
A
- Friction between two insulators
16
Q
An atom that contains 6 protons and 5 electrons has what electrical charge?
A
- Positive
17
Q
How do “like” and “unlike” charges react to one another?
A
Unlike charges attract each other, like charges repel each other
18
Q
What is/are the term(s) applied to the space between and around charged bodies in which their influence is felt?
A
- Electric field of force
19
Q
Electrostatic lines of force are drawn in which of the following manners?
A
- Entering negative charge, leaving positive charge
20
Q
Which of the following devices use magnetism?
A
- High-fidelity speakers
21
Q
Magnetic materials have which of the following qualities?
A
- They are attracted by magnets
- They can be magnetized
- BOTH 1 AND 2
22
Q
Ferromagnetic materials have which of the following qualities?
A
- They are relatively easy to magnetize
23
Q
A material with low reluctance and high permeability such as iron or soft steel is used to make what type of magnet?
A
- Temporary
24
Q
The ability of a material to retain magnetism is called
A
- retentivity
25
The law of magnetic poles states which of the following relationships?
4. Like poles repel, unlike poles attract
26
The north indicating pole of a compass needle is attracted to which of the following poles of the earth?
1. The geographic north pole
27
Weber’s theory of magnetism assumes that magnetic material is composed of
4. atoms with electrons spinning different directions
28
According to the domain theory, if an atom with 26 electrons has 20 electrons spinning counter clock-wise, the atom is considered to be
4. magnetized
29
If a glass plate is placed over a magnet and iron filings are sprinkled over the glass, a pattern will be visible. What does this pattern indicate?
1. The magnetic field
30
An imaginary line used to illustrate a magnetic effect is known as a/an
3. magnetic line of force
31
Which of the following is NOT a property of magnetic lines of force?
3. They cross each other at right angles
32
A magnetic shield or screen used to protect a delicate instrument should be made of which of the following materials?
3. Soft iron
33
Bar magnets should be stored in which of the following manners?
4. In pairs with a north pole and a south pole together
34
What is the term applied to the ability to do work?
2. Energy
35
An object that is in motion has what type of energy?
1. Kinetic
36
A book sitting on a shelf has what kind of energy?
2. Potential
37
Which of the following term(s) apply(ies) to the difference of potential between two bodies?
1. Voltage
2. Electromotive force
3. BOTH 1 AND 2
38
Which of the following terms is equal to “2.1 kV?”
2. 2100 V
39
250μV is equal to which of the following terms?
1. .25 mV
2. .00025 V
3. 250 x 10-6 V
4. ALL OF THE ABOVE
40
What is the general term that describes a device which supplies a voltage?
1. A voltage source
41
In addition to friction, magnetism, and chemical action, which of the following methods can be used to produce a voltage?
1. Pressure
2. Heat
3. Light
4. EACH OF THE ABOVE
42
Voltage producing method of:
| Radio receiver’s oscillator
2. Pressure
43
Voltage producing method of:
| Thermocouple
1. Heat
44
Automobile battery
4. Chemical action
45
Automobile generator
3. Magnetism
46
Flashlight cell
4. Chemical action
47
Current in an electric circuit is caused by which of the following actions?
1. Electrons moving from negative to positive
48
When directed drift takes place, at what speed does the effect take place?
2. 186,000 miles per second
49
If the voltage in a circuit increases, what happens to the current?
1. Current increases
50
Which of the following values is equal to 100mA?
3. 0.10 ampere
51
What symbol is used to represent the ohm?
Ω
52
If low weight is the major factor, which of the following materials should be used as a conductor?
1. Aluminum
53
What material is MOST widely used as a conductor in electrical equipment?
2. Copper
54
Resistance of a conductor will increase with which of the following changes to the cross-sectional area and length of the conductor?
4. Cross-sectional area is decreased, length is decreased
55
A material whose resistance decreases as the temperature increases has what temperature coefficient?
2. Negative
56
A material whose resistance remains constant as the temperature increases has what temperature coefficient?
3. Zero
57
Which of the following units is NOT a unit of conductance?
4. Ohm
58
Resistance bears which, if any, of the following relationships to conductance?
2. A reciprocal relationship
59
Which of the following schematic symbols is used to represent a resistor?
GOT TO GET PIX
60
How is the ability of a resistor to dissipate heat indicated?
1. By the wattage rating
61
Carbon resistors have which of the following disadvantages?
3. The resistance value changes with age
62
Which of the following types of resistors will overcome the disadvantages of a carbon resistor?
4. Wirewound resistor
63
What is the total number of connections on (a) a rheostat and (b) a potentiometer?
2. (a) Two (b) three
64
Which, if any, of the following types of variable resistors is used to control a large amount of current?
3. Wirewound potentiometer
65
A carbon resistor is color-coded orange, orange, orange. What is the resistance value of this resistor?
3. 33.0 kΩ
66
What are the allowable limits of ohmic value in a resistor color coded blue, green, yellow, gold?
1. 682.5 kΩ to 617.5 kΩ
67
Of the following, which color of the fifth band on a resistor indicates the LEAST
chance of failure? BROWN, RED, ORANGE, YELLOW
YELLOW
68
ACRONYM for simplifying the color code
Bad, Boys, Run, Over, Yellow, Gardenias, Behind, Victory, Garden, Walls
69
The color of the first band of a resistor indicates what?
the value of the first significant digit
70
the color of the second band of a resistor indicates what?
the value of the second significant digit
71
The color of the third band of a resistor represents what?
a decimal multiplier by which the first two digits must be multiplied to obtain the resistance value
72
The color of the fourth band of a resistor represents what?
The tolerance band, which usually does not present too much of a problem
73
Which band would present a problem if mistaken?
The third band, because the value will be too high or too low.
74
When the third band is black, the resistor's value is
LESS THAN 100 OHMS
75
When the third band is brown, the resistor's value is
IN HUNDREDS OF OHMS
76
When the third band is red, the resistor's value is
IN THOUSANDS OF OHMS
77
When the third band is orange, the resistor's value is
IN TEN THOUSANDS OF OHMS
78
When the third band is yellow, the resistor's value is
IN HUNDREDS OF THOUSANDS OF OHMS
79
When the third band is green, the resistor's value is
IN MEGOHMS
80
When the third band is blue, the resistor's value is
IN TENS OF MEGOHMS OR MORE
81
When the third band is silver, the resistor's value is
MULTIPLIED BY 0.01
82
When the third band is gold, the resistor's value is
MULTIPLIED BY 0.1
83
If there is no fourth band, the resistor has
a 20% tolerance
84
If the fourth band is silver, the resistor has
a 10% tolerance
85
If the fourth band is gold, the resistor has
a 5% tolerance
86
What does it mean when resistors have a fifth band?
These resistors conform to military specifications, which indicates the reliability lever per 1,000 hours of operation
87
If the fifth band is brown, it has
a 1% level
88
If the fifth band is red, it has
a 0.1% level
89
If the fifth band is orange, it has
a 0.01% level
90
If the fifth band is yellow, it has
a 0.001% level
91
If the first or second band is black, that number is
0
92
If the first or second band is brown, that number is
1
93
If the first or second band is red, that number is
2
94
If the first or second band is orange, that number is
3
95
If the first or second band is yellow, that number is
4
96
If the first or second band is green, that number is
5
97
If the first or second band is blue, that number is
6
98
If the first or second band is violet, that number is
7
99
If the first or second band is gray, that number is
8
100
If the first or second band is white, that number is
9
101
If the fourth band is brown, the resistor has
1% tolerance
102
If the fourth band is red, the resistor has
2% tolerance
103
What is matter, and in what three states is it found?
Anything that occupies space and has weight. Solids, liquids, gases.
104
What is an element?
A substance which cannot be reduced to a simpler substance by chemical means.
105
What is a compound?
A substance consisting of two or more elements.
106
What is the difference between a compound and a mixture?
A compound is a chemical combination of elements that cannot be separated by physical means. A mixture is a physical combination of elements and compounds that are not chemically combined.
107
What is a molecule?
A chemical combination of two or more atoms.
108
What are the three types of subatomic particles, and what are their charges?
Electrons-negative, protons-positive, and neutrons-neutral
109
What is energy of motion called?
Kinetic energy
110
How is invisible light changed to visible light in a fluorescent light?
Invisible light photons (ultraviolet) bombard the phosphor atom in the light tube. The phosphor atoms emit visible light photons.
111
What determines the valence of an atom?
The number of electrons in the outer shell
112
What is an ion?
An atom with more or less than its normal number of electrons
113
What determines whether a substance is a conductor or an insulator?
The number of valence electrons
114
How is a negative charge created in a neutral body?
Through the accumulation of excess electrons
115
How are static charges created?
By friction
116
What is the electrical charge of an atom which contains 8 protons and 11 electrons?
Negative
117
What is the relationship between charged bodies?
Like charges repel, and unlike charges attract with a force directly proportional to the product of their charges and inversely proportional to the square of the distance between them.
118
What is an electrostatic field?
The space between and around charged bodies
119
In what direction are electrostatic lines of force drawn?
Leaving positive, entering negative.
120
What are some examples of electrical equipment which use magnetism?
Motors, generators, speakers, computers, televisions, tape recorders, and many others.
121
What are magnetic materials?
Those materials that are attracted by magnets and have the ability to become magnetized.
122
What characteristics do all ferromagnetic materials have in common?
The relative ease with which they are magnetized
123
What type of magnetic material should be used to make a temporary magnet?
A material that exhibits low reluctance and high permeability, such as iron or soft steel.
124
What is retentivity?
The ability of a material to retain magnetism.
125
How does the law of magnetic poles relate to the law of electric charges?
They are very similar; like charges repel, unlike charges attract, like poles repel—unlike poles attract.
126
A compass is located at the geographical North Pole. In which direction would its needle point?
To the magnetic north pole.
127
Using Weber’s molecular theory of magnetism, describe the polarity of the magnetic poles produced by stroking a magnetic material from right to left with the south pole of a magnet.
South pole at the right, north pole at the left.
128
What is the difference between the domain theory and Weber’s theory of magnetism?
The domain theory is based upon the electron spin principle; Weber’s theory uses the concept of tiny molecular magnets.
129
Refer to figure 1-13. For what purpose would you sprinkle iron filings on the glass plate?
To enable you to "see" the magnetic field.
130
Refer to figure 1-13. What pattern would be formed if sawdust was sprinkled on the glass instead of iron filings?
No specific pattern, sawdust is a nonmagnetic material.
131
What is a magnetic line of force?
An imaginary line used to illustrate magnetic effects.
132
In what way do magnetic lines of force differ from electrostatic lines of force?
Electrostatic lines of force do not form closed loops.
133
How should a delicate instrument be protected from a magnetic field?
By shielding or surrounding the instrument with a soft iron case, called a magnetic shield or screen
134
How should bar magnets be stored?
In pairs, with opposite poles together to provide a complete path for magnetic flux.
135
What is the definition of energy?
The ability to do work.
136
What type of energy does a rolling stone have?
Kinetic energy.
137
What kind of energy does the stone have if it is at rest at the top of a hill?
Potential energy.
138
What term describes voltage or emf?
Difference of potential.
139
Convert 2.1 kV to volts.
2100 volts.
140
Express the following in more simple terms. (a) 250,000 volts, (b) 25,000,000 microvolts, (c) 0.001 millivolt.
(a) 250 kV, (b) 25 V, (c) 1 μV.
141
A device which supplies a voltage is commonly referred to by what name?
A voltage source.
142
Name the six methods of producing a voltage.
Friction, pressure, heat, light, chemical action, and magnetism.
143
The piezoelectric effect is an example of a voltage being produced by what method?
Pressure.
144
A thermocouple is a device that produces voltage by what method?
Heat.
145
A battery uses what method to produce a voltage?
Chemical.
146
A generator uses what method to produce a voltage?
Magnetic
147
According to electron theory, an electric current flows from what potential to what potential?
Electron theory assumes that electron flow is from negative to positive.
148
The effects of directed drift take place at what rate of speed?
The speed of light (186,000 miles per second, 300,000,000 meters per second).
149
What is the relationship of current to voltage in a circuit?
Current increases as voltage increases.
150
Convert 350 mA to amperes.
0.35 amperes.
151
What is the symbol for ohm?
Ω
152
When would silver be used as a conductor in preference to copper?
When the need for conductivity is great enough to justify the additional expense.
153
Which wire has the least resistance? Wire A-copper, 1000 circular mils, 6 inches long. Wire B-copper, 2000 circular mils, 11 inches long.
Wire B.
154
Which temperature coefficient indicates a material whose resistance increases as temperature increases?
Positive.
155
What term describes a material whose resistance remains relatively constant with changes in temperature?
Zero temperature coefficient.
156
What is the unit of conductance and what other term is sometimes used?
The mho (v), siemens.
157
What is the relationship between conductance and resistance?
They are reciprocals of each other.
158
What is schematic symbol for a resistor?
JAGGED LINE
159
What does the wattage rating of a resistor indicate?
Its ability to dissipate heat.
160
What are the two disadvantages of carbon-type resistors?
1. Change value with age. 2. Limited power capacity.
161
What type resistor should be used to overcome the disadvantages of the carbon resistor?
The wirewound resistor.
162
Describe the differences between the rheostat connections and those of the potentiometer.
The rheostat may have two connections, one fixed and one moveable; the potentiometer always has three connections, one moveable and two fixed.
163
Which type of variable resistor should you select for controlling a large amount of current?
The rheostat.
164
A carbon resistor has a resistance of 50 ohms, and a tolerance of 5 percent. What are the colors of bands one, two, three, and four, respectively?
The bands are green, black, black, and gold.
165
A carbon resistor has the following color bands: The first band is yellow, followed by violet, yellow, and silver. What is the ohmic value of the resistor?
470,000 ohms (470 kilohms).
166
The same resistor mentioned in question 63 has a yellow fifth band. What does this signify?
The resistor’s chance of failure is 0.001 percent for 1000 hours of operation.
167
A resistor is handed to you for identification with the following color code: the first band is blue, followed by gray, green, gold, and brown. What is the resistor’s value?
6,800,000 ohms (6.8 megohms), with 5% tolerance, and a 1% reliability level.
