3.3: Electrical Terminology Flashcards
1
Q
- Potential difference (PD) is:
(a) The difference in pressure between two point in a circuit.
(b) The difference in pressure that might exist in a circuit.
(c) The difference between a positive and negative point in a circuit only.
A
(a) The difference in pressure between two point in a circuit.
2
Q
- PD is measured in;
(a) Amps
(b) Volts.
(c) Mohs.
A
(b) Volts.
3
Q
- The symbol for voltage is:
(a) E
(b) V
(c) I
A
(b) V
4
Q
- An electrical current is defined as
(a) The rate of flow of electrons in a circuit.
(b) A quantity of electrons in a circuit,
(c) Pressure that cause electrons to flow.
A
(a) The rate of flow of electrons in a circuit.
5
Q
- The symbol for current is:
(a) I
(b) C
(c) A
A
(a) I
6
Q
A
(c) Current will flow from point B to point A
Note: Conventional current flow is systems that are designed assuming flow is from positive to negative
While Electron flow is what actually happens which is flow from negative to positive
7
Q
- Current is;
(a) The rate of flow of electrons in a circuit.
(b) A quantity of electrons, that operates in a circuit.
(c) The pressure that causes electrons to flow.
A
(a) The rate of flow of electrons in a circuit.
8
Q
- Three effects of current in a circuit is;
(a) Heat, light and magnetism.
(b) Chemical, heat and magnetism.
(c) Magnetism, heat and friction.
A
(a) Heat, light and magnetism.
9
Q
- A Coulomb is a
(a) Quantity of electrons.
(b) The rate of flow of electrons.
(c) The opposition to the flow of electrons.
A
(a) Quantity of electrons.
10
Q
- The symbol for a Coulomb is;
(a) C
(b) B
(c) Q
A
(a) C
11
Q
- What is 3.25 volts in millivolts
(a) 3.25 millivolts
(b) 3,250 millivolts
(c) 325,000 millivolts
A
(b) 3,250 millivolts
12
Q
- Electromotive force is measured in
(a) Watts
(b) Ohms
(c) Volts
A
(c) Volts
13
Q
- 20 amperes flow for 20 seconds. How many coulombs has flowed?
(a) 400
(b) 20
(c) 1
A
(a) 400
Note: Q = I * T where Q is charge in Coulombs, I is current in Amps and T is time in seconds
Q = (20A) * (20s), Q = 400 C
14
Q
- A volt can be considered to be a
(a) unit of electrical pressure
(b) quantity of electrical energy
(c) unit of electrical power
A
(a) unit of electrical pressure
15
Q
- If 2 coulombs flowed through a circuit in 2 seconds, the circuit would have
(a) 2 volts PD
(b) 2 amps
(c) 1 amp
A
(c) 1 amp
Note: 1 Amp = 1 Coulomb/sec
Q = I * T where Q is charge in Coulombs, I is current in Amps and T is time in seconds
(2C) = I * (2s)
I = 2/2, I = 1A
16
Q
- A coulomb is
(a) one ampere per second
(b) one ampere x second
(c) one second per ampere
A
(a) one ampere per second
Note: 1 Ampere is also one Coulomb per second aswell
17
Q
- The potential difference between two conductors which are insulated from each other is measured in:
(a) Ohms
(b) Volts
(c) Amperes
A
(b) Volts
18
Q
- An aircraft battery has a capacity of 10 AH. How many Coulombs are stored in the battery?
(a) 36.000 Coulomb
(b) 6,000 Coulomb
(c) 360 Coulomb
A
(a) 36.000 Coulomb
Remember: 1 amp = 1 Coulomb / second
and also 1 Coulomb = 1 amp / second
19
Q
- The SI unit of work is
(a) Joules per second (Watts)
(b) Kilogram metres – force
(c) Joules per metre
DODGY QUESTION <>
A
(c) Force x metre
Remember: Work is force times a distance
Power is Work (
20
Q
- Power is the rate of doing work. It is measured in
(a) joules/second
(b) watts/second
(c) joules x seconds
A
(a) joules/second
21
Q
- The Watt can be expressed as
(a) Joules per second
(b) Joules x seconds
(c) Seconds per Joul
A
(a) Joules per second
22
Q
- .002KV equals
(a) 20 volts.
(b) 2.0 volts.
(c) 0 .2 volt.
A
(b) 2.0 volts.
23
Q
- When referring to an electrical circuit diagram, what point is considered to be at zero voltage?
(a) The circuit breaker.
(b) The ground reference.
(c) The switch.
A
(b) The ground reference.
24
Q
- In a circuit, conventional current flow states that;
(a) Electrons flow from positive to negative side of a circuit.
(b) Electrons flow from negative to positive side of a circuit,
(c) Electrons flow in one direction in the circuit.
A
(a) Electrons flow from positive to negative side of a circuit.
Note:
Conventional flow - positive to negative
Electron flow - actually what happens in real life - electrons flow from negative to positive
25
73. In a circuit, electron flow states that;
(a) Electrons flow from positive to negative side of a circuit.
(b) Electrons flow from negative to positive side of a circuit,
(c) Electrons flow in one direction in the circuit.
**(b) Electrons flow from negative to positive side of a circuit,**
**Note:**
**Electron flow -** negative to positive
**Conventional flow -** positive to negative
26
74. Resistance is defined as;
(a) Ease which current flow through a circuit.
(b) Opposition to current flow through a circuit,
(c) The speed at which electrons flow in a circuit.
**(b) Opposition to current flow through a circuit,**
27
75. Resistance is measured in,
(a) Ohms
(b) Mohs
(c) Coulombs
**(a) Ohms**
28
76. Which of the following materials has the highest conductivity for the same crossectional area and length
(a) Copper
(b) Aluminium
(c) Glass
**(a) Copper**
29
77. Which of the following materials has the highest conductivity for the same crossectional area and length
(a) Aluminium
(b) Gold
(c) Silver
**(c) Silver**
Remeber So Cah GA
30
78. Calculate the Conductance of a substance with 20 ohms Resistance
(a) 0.005 mho
(b) 0.05 mho
(c) 0.5 mho
**(b) 0.05 mho**
Conductance (mho /siemens) = (upside down resistance symbol/ s) = 1 / R
where R is resistance
Conductance symbol on diagram is G
31
79. Resistance of a conductor will increase with which of the following changes to the cross-sectional area and length of the conductor?
(a) Cross-sectional area is increased, length is increased
(b) Cross-sectional area is increased, length is decreased
(c) Cross-sectional area is decreased, length is increased
(d) Cross-sectional area is decreased, length is decreased
**(c) Cross-sectional area is decreased, length is increased**
32
80. A material whose resistance decreases as the temperature increases has what temperature coefficient?
(a) Positive
(b) Negative
(c) Zero
(d) Neutral
**(b) Negative**
''Temperature coefficient of resistance symbolises the resistance change factor per degree of temperature change
For pure metals, this coefficient is a positive number, meaning that resistance increases with increasing temperature. For the elements carbon, silicon, and germanium, this coefficient is a negative number, meaning that resistance decreases with increasing temperature.
For some metal alloys, the temperature coefficient of resistance is very close to zero, meaning that the resistance hardly changes at all with variations in temperature ( a good property if you want to build a precision resistor out of metal wire).
33
81. A semiconductor has what type of temperature coefficient of resistance:
(a) Positive
(b) Negative
(c) Zero
**(b) Negative**
## Footnote
''Temperature coefficient of resistance symbolises the resistance change factor per degree of temperature change
For pure metals, this coefficient is a positive number, meaning that resistance increases with increasing temperature. For the elements carbon, **silicon, and germanium**, this coefficient is a negative number, meaning that resistance decreases with increasing temperature.
For some metal alloys, the temperature coefficient of resistance is very close to zero, meaning that the resistance hardly changes at all with variations in temperature ( a good property if you want to build a precision resistor out of metal wire).
**Examples of semi-conductors are Silicon Germanium, aluminium**
34
82. What unit is used to express electrical power?
(a) Volt.
(b) Watt.
(c) Ampere.
**(b) Watt.**
35
83. How is the ability of a resistor to dissipate heat indicated?
(a) By the wattage rating
(b) By the voltage rating
(c) By the resistance rating
(d) By the tolerance
**(a) By the wattage rating**
''The ability of the resistor to dissipate heat depends upon the design of the resistor itself. This ability to dissipate heat depends on the amount of surface area which is exposed to the air. A resistor designed to dissipate a large amount of heat must therefore have a large physical size. The heat dissipating capability of a resistor is measured in Watts.''
36
84. The factors affecting resistance of a conductor are;
(a) Length, materials, size of electrons and size of protons.
(b) Length, temperature, crystal structure and weight,
(c) Material, length, cross section Area and Temperature.
**(c) Material, length, cross section Area and Temperature.**
37
85. Copper is a ;
(a) Better conductor than Aluminium.
(b) Poorer conductor than Aluminium,
(c) Is equal to Aluminium as a conductor.
**(a) Better conductor than Aluminium.**
38
86. If a material has a positive temperature coefficient of resistance, it means that:
(a) As the temperature rises the resistance decreases.
(b) As the temperature falls the resistance stay the same
(c) As the temperature rises the resistance increases.
**(c) As the temperature rises the resistance increases.**
''Temperature coefficient of resistance symbolises the resistance change factor per degree of temperature change
For pure metals, this coefficient is a positive number, meaning that resistance increases with increasing temperature. For the elements carbon, silicon, and germanium, this coefficient is a negative number, meaning that resistance decreases with increasing temperature.
For some metal alloys, the temperature coefficient of resistance is very close to zero, meaning that the resistance hardly changes at all with variations in temperature ( a good property if you want to build a precision resistor out of metal wire).
39
87. Copper has a:
(a) Positive temperature coefficient.
(b) Negative temperature coefficient.
(c) Neutral temperature coefficient.
**(a) Positive temperature coefficient.**
## Footnote
''Temperature coefficient of resistance symbolises the resistance change factor per degree of temperature change
For pure metals, this coefficient is a positive number, meaning that resistance increases with increasing temperature. For the elements carbon, silicon, and germanium, this coefficient is a negative number, meaning that resistance decreases with increasing temperature.
For some metal alloys, the temperature coefficient of resistance is very close to zero, meaning that the resistance hardly changes at all with variations in temperature ( a good property if you want to build a precision resistor out of metal wire).
40
88. Conductance is defined as the:
(a) The ease at which current flows through a conductor.
(b) The opposition to current flow through a conductor.
(c) The amount of heat a conductor emits with current flow.
**(a) The ease at which current flows through a conductor.**
41
89. If the resistance of an electrical circuit is increased
(a) the voltage will increase
(b) the current will increase
(c) the current will decrease
**(c) the current will decrease**
42
90. The voltage drop in a conductor of known resistance is dependant on:
(a) the voltage of the circuit
(b) the amperage of the circuit
(c) only the resistance of the circuit and does not change in either voltage or amperage.
**(b) the amperage of the circuit**
43
91. In general, increasing the cross sectional area of an electrical cable
(a) enables it to carry more current
(b) enables it to carry more voltage
(c) increases its resistance
**(a) enables it to carry more current**
44
92. The amount of electron flow through a conductor would be increased by the greatest amount, if the:
(a) Cross-sectional area and length were both increased
(b) Cross-sectional area and length were both decreased
(c) Cross-sectional area increased and length decreased
**(c) Cross-sectional area increased and length decreased**
45
93. In which of the following cases will a potential difference not exist?
(a) between two identical positive charges
(b) between a positive charge and an equal negative charge
(c) between a charged body and an uncharged body
**(a) between two identical positive charges**
46
94. Current in an electric circuit is caused by which of the following actions?
(a) Electrons moving from negative to positive
(b) Electrons moving from positive to negative
(c) Protons moving from negative to positive
(d) Protons moving from positive to negative
**(a) Electrons moving from negative to positive**
47
**Option C: photodiode**
48
**Option C: the magnitude of the EMF is directly proportional to the rate of change of flux**
49
**Option A: 1000 mA**
50
**Option C: impedance**
51
**Option B: Current = e.m.f divided by resistance**
52
**Option A: MMF**
53
**Option A: Generators**
54
**Option A: Kilogram metres-force**
Work is measured in joules, which is Newton.metres or kilogram.metres force (since Newtons are Kilograms force)
55
**Option c: one ampere per second**
Current (Amps) = Charge (Coulombs) per second
56
**Option B: electrons from a negatively charged area to a positively charged area**
57
**Option C: unit of electrical pressure**
Electrical pressure' is sometimes used instead of voltage, due to its analogy to a head of pressure in fluids
58
**Option A: 3,250 millivolts**
59
**Option C: Volts**
EMF is another term for voltage, or potential difference (PD) or electrical pressure, all measured in volts
60
Option A: the algebraic sum of all voltages entering or leaving a series of components will be equal to zero
61
**Option A: inductance**
62
**Option C: mutual induction**
63
**Option B: the loss of continuity will prevent its component from functioning**
64
**Option C: Tesla**
65
**Option B: 0.000,001 Farads**
66
**Option A: inductive reactance**
67
**Option A: An ammeter**
A shunt is used to change the working range of an ammeter, by ‘shunting’ around the ammeter, a major portion of the current being measured.
68
**Option A: the corkscrew rule**
69
**Option A: Joules per second**
Power = energy (joules) / time (seconds)
70
**Option C: motors**
71
**Option B: Faraday's Law**
72
**Option C: Joules per second**
Power = Energy(J) / Time(s)
73
**Option A: B**
74
**Option C: the corkscrew rule**
75
**Option C: mutual inductance**
76
**Option C: -L dl / dt**
77
**Option C: permeability**
78
**Option A: I \* N**
MMF (symbol H) = amps \* turns (units are ampere turns)
79
**Option B: Faraday's Law**
Faraday's Law is induced EMF is directly proportional to the rate of change of flux
80
**Option B: Fleming's right hand rule**
**If current is induced, created therefore must be generator - Ryan Gigs (Right Hand Rule - Generator)**
81
(assuming conventional current flow)
**Option A: Flemings left hand rule**
**Note: If current going into armature, must be motor and therefore Lionel Messi (Left Hand Rule for Motor)**
82
**Option B: Siemen**
Conductance is 1/R and is measured in Siemens /Mho
83
**Option B: Ohm metre**
84
**Option B: 1/R**
Conductance (mho/siemens) (diagram symbol G) is the inverse of resistivity
G = 1/R
85
Option B: Watt
86
Option A: Newton-meter which is Joules
Work has the same unit as energy i,e Nm or Joule
87
Option A: Joule
88
Option A: voltage
Potential difference, electromotive force, electrical pressure, are all terms for voltage
89
Option A: inductive reactance
‘’L'' is for inductance, ‘’X'' is for reactance
90
Option B: current is directly proportional to the EMF
91
Option C: 1 Henry
1 Henry = 1 Volt per Amp per Second
92
Option B: resistance
93
Option C: closed loop networks
94
Option C: Joule
95
Option A: Faraday's law
96
6. 3 amperes flow for 15 seconds. How many coulombs has flowed?
(a) 5
(b) 45
(c) 135
(b) 45
Q = I\*T
Where Q is charge in Coulombs, I is current in Amps and T is time in seconds
Q = (3A)\*(15s) , Q = 45C
