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WorksheetsChapter 5 quizz
Total questions: 91
Worksheet time: 23hrs 45mins
What law is used to calculate the resistance, voltage across, or current through an electric device?
Kirchhoff's law
Faraday's law
Ohm's law
Joule's law
Which term describes the opposition that conductors present to current?
Conductance
Resistance
Capacitance
Inductance
What must be known to calculate the resistance of a material given its length, cross-sectional area, and resistivity?
Ohm's law
The American Wire Gauge table
The voltage-current characteristic
The color code
What can you use to calculate the resistance of a length of wire?
The color code
The American Wire Gauge table
A potentiometer
A thermistor
What is the term for the specific resistance of a material?
Conductivity
Resistivity
Reactance
Impedance
Who is the ohm, the unit of resistance, named after?
Isaac Newton
Georg Simon Ohm
James Watt
Alessandro Volta
What is the relationship between voltage (E), current (I), and resistance (R) according to Ohm's Law?
E = IR
E = I/R
E = R/I
I = ER
What does the letter symbol 'R' stand for in the context of Ohm's Law?
Ratio
Reactance
Resistance
Radiance
What is the SI unit of electric resistance?
Ampere
Volt
Ohm
Watt
What does one ohm equal?
According to Ohm's Law, if the temperature of the conductor does not change, what happens to the current when the applied voltage is doubled?
The current remains the same.
The current is halved.
The current is doubled.
The current is tripled.
What is the resistance (R) in ohms when the voltage drop (V) across the resistance is 6.0 V and the current (I) through the resistance is 150 mA?
4 Ω
40 Ω
400 Ω
0.4 Ω
According to Ohm's law as presented in the image, which formula correctly represents the relationship between resistance (R), voltage (V), and current (I)?
R = VI
R = V/I
R = I/V
R = V + I
If the voltage drop across a resistance is 480 mV and the current through the resistance is 20 μA, what is the calculated resistance?
24 Ω
240 Ω
2.4 kΩ
24 kΩ
What happens to the energy from the source when a voltage is applied to a conductor, as described in the section "The Nature of Resistance"?
It is entirely converted into potential energy within the conductor.
It is transferred to the free electrons as kinetic energy.
It is stored within the conductor without any transfer.
It is immediately dissipated as sound within the conductor.
What happens to the speed at which electrons drift in a material when there are more collisions between free electrons and atoms?
The speed increases
The speed remains the same
The speed decreases
The speed varies randomly
What is the relationship between the rate of collisions in a material and its resistance?
Directly proportional
Inversely proportional
No relationship
The resistance decreases as the rate of collisions increases
Why might some applications that produce heat from current flowing through a resistance require ventilation or other cooling?
To increase the heat production
To prevent the waste heat from damaging the circuit
To make the device glow
To reduce the resistance of the circuit
What is the effect of adding a resistor to a circuit with a lamp and a voltage source, as shown in Figure 5-2?
It increases the brightness of the lamp
It has no effect on the circuit
It decreases the current and dims the lamp
It converts the lamp into a resistor
According to the text, how does the resistance of a conductor relate to its length?
It is inversely proportional to its length
It is directly proportional to its length
It is unrelated to its length
It decreases with the increase in length
What happens to the resistance of a wire if it has twice the cross-sectional area of another wire with the same material and length?
The resistance is twice as much
The resistance is the same
The resistance is half as much
The resistance is four times as much
The resistance of a conductor is inversely proportional to which of the following physical properties?
Its length
Its cross-sectional area
Its temperature
Its composition
Which of the following statements is true regarding the resistance of a conductor?
It is independent of the conductor's composition.
It is directly proportional to the conductor's cross-sectional area.
It is inversely proportional to the conductor's length.
It is dependent on the composition of the conductor.
According to the formula for resistivity given in the image, if the length (l) of a conductor is doubled and the cross-sectional area (A) remains the same, how does the resistance (R) change?
It remains the same.
It is halved.
It is doubled.
It is quadrupled.
In the example provided in the image, what is the resistance of 50 m of wire with a cross-sectional area of 0.25 mm² if the original wire has a resistance of 0.017 Ω and a cross-sectional area of 1.0 mm²?
0.085 Ω
3.4 Ω
0.34 Ω
34 Ω
What is the letter symbol for resistivity?
σ
ρ
λ
ε
What is the SI unit of resistivity?
Ohm
Ohm metre
Ohm metre squared
Ohm per metre
Which of the following materials has the highest resistivity at 20°C according to Table 5-1?
Silver
Copper (annealed)
Nichrome™ II
Gold
The resistivity of a material is defined as the resistance of a unit length of the material with what?
Unit volume
Unit mass
Unit cross-sectional area
Unit temperature
According to the formula R = l / A, if the length (l) and the cross-sectional area (A) are both 1, what does R represent?
The resistance of the conductor in ohms
The resistivity of the conductor material in ohm metres
The length of the conductor in metres
The cross-sectional area in square metres
What is the resistance at 20°C of a 200 m long aluminum conductor with a cross-sectional area of 4.0 mm²?
1.4 Ω
2.8 Ω
3.2 Ω
0.7 Ω
If the diameter of a copper wire is 0.64 mm, what is the resistance at normal room temperature of a 60 m length of this wire?
1.4 Ω
3.2 Ω
2.8 Ω
0.7 Ω
What does CM stand for in the context of electrical conductors?
Circular meter
Circular mil
Centimeter
Circular millimeter
What is the area of a circle with a diameter of one mil?
3.217 x 10⁻⁷ m²
3.217 x 10⁻⁶ m²
3.217 x 10⁻⁸ m²
3.217 x 10⁻⁹ m²
What is the formula for the area of a circle in circular mils?
A = πd^2
A = πr^2
A = d^2
A = r^2
If the diameter of a wire is 0.02800 inches, what is the cross-sectional area in circular mils?
784 CM
28 CM
0.028 CM
28.0 CM
What is the resistivity of copper at 20°C in ohm-circular mils per foot?
9.9
10.4
14.7
17.0
Which material has a higher resistivity at 20°C, aluminum or brass?
Aluminum
Brass
They have the same resistivity
The resistivity is not given
Manganin is a copper alloy that contains what percentage of manganese and nickel?
13%–18% manganese and 1%–4% nickel
10%–15% manganese and 2%–5% nickel
15%–20% manganese and 0%–3% nickel
12%–17% manganese and 3%–6% nickel
What is the resistance of a copper wire that is 0.350" in diameter and 50.0 miles long, given that the resistivity (ρ) of copper is 10.4 x 10^-6 Ω·cm?
21.6 Ω
10.8 Ω
43.2 Ω
5.4 Ω
According to the American Wire Gauge (AWG) system, what is the approximate area ratio between wire sizes that are three AWG numbers apart?
1.26
2.00
1.50
1.12
What is the relationship between the resistance per unit length for two wires that are three AWG numbers apart?
The wire with the larger AWG number has half the resistance.
The wire with the smaller AWG number has twice the resistance.
The wire with the larger AWG number has double the resistance.
The wire with the smaller AWG number has half the resistance.
What is the resistance of an aluminum wire with a diameter of 0.25 mm and a length sufficient to give a resistance of 2.25 Ω at 20°C?
2.25 Ω
4.50 Ω
1.125 Ω
0.5625 Ω
A 6.5 m length of wire has a diameter of 0.8 mm and a resistance of 0.315 Ω at 20°C. What is the likely material of this wire?
Copper
Aluminum
Gold
Silver
What is the resistance of solid copper at 20°C with an AWG gauge size of 0?
0.0983 Ω/kft
0.1289 Ω/kft
0.4035 Ω/kft
0.3931 Ω/kft
According to Table 5-3, what is the area in mm² for an AWG gauge size of 14?
2.08 mm²
2.62 mm²
3.31 mm²
2.08 mm²
Using the formula R = ρl/A, if the resistance (R) is 1.62 Ω for a length (l) of 2500 ft, and the resistivity (ρ) is 17 Ω mil/ft, what is the cross-sectional area (A) in MCM?
26.2 MCM
16.2 MCM
17.0 MCM
25.0 MCM
What AWG size matches an area of 26.2 MCM according to the example provided?
AWG #4
AWG #6
AWG #8
AWG #10
How does the resistance of most conducting materials change with temperature?
The resistance decreases linearly with temperature.
The resistance increases linearly with temperature.
The resistance does not change with temperature.
The resistance increases exponentially with temperature.
For which type of materials does the resistance decrease as the temperature increases?
Insulators
Semiconductors
Superconductors
Metals
What does the line segment CF in Figure 5-5 represent?
The resistance at zero temperature
The change in resistance with temperature for a specific material
The resistance at a fixed temperature
The temperature at which resistance is zero
According to the text, what is the relationship between R2/R1 and the temperatures T1 and T2?
R2/R1 = T2/T1
R2/R1 = (x + T2)/(x + T1)
R2/R1 = T1/T2
R2/R1 = (T2 - x)/(T1 + x)
What is the value of x for copper according to Table 5-4 in the learning material?
243
234.5
202
147
According to the example calculations provided, what is the resistance of a copper conductor at 100°C if it has a resistance of 12.0 Ω at 20°C?
15.8 Ω
10.0 Ω
12.0 Ω
20.0 Ω
Using the formula from the learning material, if a precision resistor made of constantan wire has a resistance of 10,000 Ω at 20°C, what would its resistance be when the temperature rises 20°C?
10,002 Ω
10,020 Ω
10,200 Ω
12,000 Ω
What is the resistance of a copper wire at 40°C if its length is 300 m and the cross-sectional area is 1.50 mm²?
3.44 Ω
3.71 Ω
3.90 Ω
4.05 Ω
According to the example provided, what is the temperature rise in the winding of an electric motor if the resistance changes from 0.20 Ω at 20°C to 0.22 Ω at an unknown temperature?
25°C
45°C
45.45°C
20°C
Which equation is used to estimate the resistance of any metallic conductor at any temperature?
R = ρl/A
R = ρl/(A + T)
R = ρl/(A × T)
R = ρl/(A(x + T))
What does the temperature coefficient of resistance at 20°C represent?
The resistance of a conductor at any specified temperature
The resistance of a conductor at 20°C
The proportion by which the resistance changes per degree of change in temperature from 20°C
The resistivity of the material in ohm metres at 20°C
Which equation represents the general formula for the resistance of a conductor?
R = ρl/A
R = R₁(1 + αΔT)
R = R₁ + FE + R₁
R = ρl/A (1 + αΔT)
What symbol is used to represent the temperature coefficient of resistance?
R
ρ
α
l
If the line segment CE is parallel to the temperature axis in Figure 5-5, what does CE represent?
The resistance of the conductor at 20°C
The change in resistance due to temperature change
The length of the conductor
The resistivity of the material
What is the temperature coefficient of resistance for copper at 20°C?
0.000 93
0.000 16
0.004 5
0.000 008
If a copper wire with a cross-sectional area of 1.5 mm² is 300 m long, what is the resistance of the wire at 40°C?
3.71 Ω
3.44 Ω
1.72 Ω
1.079 Ω
What is the resistance of a Nichrome™ II heating element at normal room temperature if it has a resistance of 16.0 Ω at 1500°C?
12.9 Ω
16.0 Ω
13.7 Ω
15.0 Ω
According to the information provided, what happens to the resistance if the temperature is below 20°C?
The resistance increases.
The resistance remains the same.
The resistance decreases.
The resistance becomes zero.
What is the relationship between current and voltage for most conductors, as indicated by a graph of current versus voltage?
Exponential
Inverse
Linear
Quadratic
What happens to the resistance of common conductor materials such as copper and aluminum as the temperature increases?
The resistance decreases significantly.
The resistance increases slightly.
The resistance remains constant.
The resistance becomes zero.
What type of resistors are usually made with constantan or other alloys with a temperature coefficient of almost zero?
Carbon film resistors
Wire-wound resistors
Semiconductor resistors
Variable resistors
What can vary by 10% or more from their nominal values in inexpensive, mass-manufactured resistors?
Power rating
Resistance
Voltage rating
Temperature coefficient
According to the graph in Figure 5-6, which resistor has a steeper slope indicating a smaller resistance?
5 kΩ resistor
10 kΩ resistor
Both have the same slope
The graph does not show slopes for resistors
What are precision resistors often made by depositing on?
A large ceramic block
A small ceramic cylinder
A plastic substrate
A metallic plate
What is commonly used when the current through the resistor produces less than 2 W of heat?
Wire-wound resistor
Precision resistor
Carbon-composition resistor
Ceramic-composition resistor
What determines the resistance in a carbon-composition resistor?
What is a characteristic of ceramic-composition resistors?
They are used for precision measurements
They are cheaper than carbon-composition resistors
They are useful for circuits where the resistors must withstand voltage or energy surges
They change resistance significantly with temperature
What is the primary material used in the construction of integrated circuits (ICs)?
Glass
Copper
Highly purified silicon
Carbon
What is the resistance of an ordinary 60-watt 120-V incandescent lamp at room temperature?
18 Ω
240 Ω
100 Ω
1 Ω
What is the inrush current at the instant the lamp is turned on for an ordinary 60-watt 120-V incandescent lamp?
0.50 A
6.6 A
1 A
5 A
What type of resistor can be used to limit inrush currents and has a large negative temperature coefficient?
Potentiometer
Thermistor
Varistor
Rheostat
What happens to the resistance of a thermistor when a current of 1 A passes through it for 10 to 15 s?
It increases to over 100 Ω
It remains the same
It drops to less than 1 Ω
It doubles
What are varistors commonly used for?
Amplifying electrical signals
Protecting sensitive electronics from voltage surges
Converting AC to DC current
Storing electrical energy
What is the primary material used in the construction of zinc oxide varistors?
Silicon wafers with a polymer binder
Zinc oxide or silicon carbide crystals with a clay binder
Copper oxide with a metallic binder
Aluminum oxide with a ceramic binder
What happens to the resistance of a varistor when the potential difference across it becomes greater than the threshold?
The resistance increases greatly
The resistance decreases slightly
The resistance decreases greatly
The resistance remains constant
What is the effect of temperature on the resistance of a varistor?
Temperature increases the resistance
Temperature decreases the resistance
Temperature has little effect on the resistance
Temperature inversely affects the resistance
What is the typical resistance range of a photoresistor in bright daylight?
Less than 100 Ω
100 Ω to 1 kΩ
Hundreds of kilohms to less than 100 Ω
More than 1 MΩ
What do thermistors, varistors, and photoresistors have in common?
They all use semiconductors engineered to become less conductive under specific conditions.
They all use semiconductors engineered to become more conductive under specific conditions.
They are all linear resistors with constant resistance values.
They are all used to increase the resistance in a circuit regardless of conditions.
Which component is represented by a schematic symbol with an arrow pointing upwards and a line through it?
General resistor
Thermistor
Varistor
Photoresistor
What is the purpose of the color bands on a resistor?
To indicate the manufacturer of the resistor.
To make the resistor look more visually appealing.
To indicate the nominal value, tolerance, and reliability of the resistor.
To indicate the power rating of the resistor.
How many color bands do most common resistors have?
Two or three
Three to six
Four or five
Always six
What does the fourth band on a 4-band resistor indicate?
The nominal value of the resistor in ohms.
The tolerance of the resistor.
The reliability of the resistor.
The first digit of the resistor's value.
What is indicated by the fifth band on some precision resistors?
The nominal value of the resistor in ohms.
The tolerance of the resistor.
The reliability of the resistor.
The power rating of the resistor.
