Question 1

A device with a resistance of $ 200.0 \mathrm{k}{\Omega}$ is connected to a $10.0 - \mathrm { V }$ battery. How much power does the device use?

Accepted Answer

A)  0.50 mW 
B)  20,000 kW 
C)  0.050 mW 
D)  2000 kW 
A)  0.50 mW 
B)  20,000 kW 
C)  0.050 mW 
D)  2000 kW

Question 2

The resistivity of gold is $2.44 \times 10 ^{- 8 }\Omega \cdot \mathrm { m }$ at a temperature of 20°C. A gold wire that is 0.50 mm in diameter and 44 cm long carries a current of 380 mA. How many electrons each second pass a given cross section of the wire at 20°C? (e = 1.60 × 10-19C)

Accepted Answer

A)  2.4 × 1018 
B)  2.4 × 1017 
C)  1.2 × 1022 
D)  2.8 × 1014 
E)  6.3 × 1015 
A)  2.4 × 1018 
B)  2.4 × 1017 
C)  1.2 × 1022 
D)  2.8 × 1014 
E)  6.3 × 1015

Question 3

A 120-m long metal wire having a resistivity of 1.68 × 10-8 Ω ∙ m has a resistance of 6.0 Ω. What is the diameter of the wire?

Accepted Answer

A)  0.065 mm 
B)  0.65 mm 
C)  0.65 cm 
D)  0.65 m 
A)  0.065 mm 
B)  0.65 mm 
C)  0.65 cm 
D)  0.65 m

Question 4

The heating element of a toaster is a 5.4-m length of nichrome wire of diameter 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 Ω ∙ m. The toaster is designed to operate at a voltage of 120 V. How much power does it draw in normal operation?

Accepted Answer

A)  370 W 
B)  360 W 
C)  380 W 
D)  400 W 
E)  410 W 
A)  370 W 
B)  360 W 
C)  380 W 
D)  400 W 
E)  410 W

Question 5

Calculate the current through a 10.0-m long 22-gauge nichrome wire with a radius of 0.321 mm if it is connected across a 12.0-V battery. The resistivity of the nichrome is 1.00 × 10-6 Ω ∙ m.

Accepted Answer

A)  30.9 A 
B)  61.8 A 
C)  0.388 A 
D)  0.776 A 
A)  30.9 A 
B)  61.8 A 
C)  0.388 A 
D)  0.776 A

Question 6

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?

Accepted Answer

A)  1/(resistance) 
B)  resistance 
C)  potential 
D)  (potential)2 
E)  1/(potential) 
A)  1/(resistance) 
B)  resistance 
C)  potential 
D)  (potential)2 
E)  1/(potential)

Question 7

The figure shows electrons passing through a resistor. The arrow shows the direction in which the electrons are moving. Which of the following statements are correct? (There could be more than one correct choice.)

Accepted Answer

A)  The electrons are moving slower at point b than at point a. 
B)  The electric potential is higher at point b than at point a. 
C)  The electric potential is lower at point b than at point a. 
D)  The electrons are losing electric potential energy as they move through the resistor from a to b. 
E)  The speed of the electrons at point b is the same as it is at point a. 
A)  The electrons are moving slower at point b than at point a. 
B)  The electric potential is higher at point b than at point a. 
C)  The electric potential is lower at point b than at point a. 
D)  The electrons are losing electric potential energy as they move through the resistor from a to b. 
E)  The speed of the electrons at point b is the same as it is at point a.

Question 8

If a charge of 11.4 C passes through a computer in 1.75 min, what is the average current through the computer?

Accepted Answer

The answer of If a charge of 11.4 C passes...

Question 9

The power rating of a 400-Ω resistor is 0.25 W. What is the maximum voltage you can safely connect across its ends?

Accepted Answer

A)  10 V 
B)  20 V 
C)  30 V 
D)  40 V 
E)  50 V 
A)  10 V 
B)  20 V 
C)  30 V 
D)  40 V 
E)  50 V

Question 10

A rod is 4.0 m long and has a square cross-section that is 1.5 cm on each side. An ohmmeter measures 0.040 Ω across its ends. What is the resistivity of the material from which this rod is made?

Accepted Answer

A)  0.023 Ω ∙ m 
B)  0.015 Ω ∙ m 
C)  1.5 × 10-4 Ω ∙ m 
D)  2.3 × 10-6 Ω ∙ m 
A)  0.023 Ω ∙ m 
B)  0.015 Ω ∙ m 
C)  1.5 × 10-4 Ω ∙ m 
D)  2.3 × 10-6 Ω ∙ m

Question 11

How much current will be flowing through a $57.0 - \mathrm { m }$ length of copper wire with radius 0.0 ${~mm}$ if it is connected to a source supplying 62.0 ${~V} ?$ The resistivity of the metal is 1.68 × 10-8 Ω ∙ m.

Accepted Answer

A)  0 A 
B)  0 × 108 A 
C)  0 nA 
A)  0 A 
B)  0 × 108 A 
C)  0 nA

Question 12

When the current through a resistor is increased by a factor of 4, the power dissipated by the resistor

Accepted Answer

A)  decreases by a factor of 4. 
B)  decreases by a factor of 16. 
C)  increases by a factor of 16. 
D)  increases by a factor of 4. 
E)  increases by a factor of 2. 
A)  decreases by a factor of 4. 
B)  decreases by a factor of 16. 
C)  increases by a factor of 16. 
D)  increases by a factor of 4. 
E)  increases by a factor of 2.

Question 13

If the resistance in a constant voltage circuit is doubled, the power dissipated by that circuit will

Accepted Answer

A)  increase by a factor of two. 
B)  increase by a factor of four. 
C)  decrease to one-half its original value. 
D)  decrease to one-fourth its original value. 
A)  increase by a factor of two. 
B)  increase by a factor of four. 
C)  decrease to one-half its original value. 
D)  decrease to one-fourth its original value.

Question 14

You are given a copper bar of dimensions 3 cm × 5 cm × 8 cm and asked to attach leads to it in order to make a resistor. If you want to achieve the largest possible resistance, you should attach the leads to the opposite faces that measure

Accepted Answer

A)  3 cm × 5 cm. 
B)  3 cm × 8 cm. 
C)  5 cm × 8 cm. 
D)  Any pair of faces produces the same resistance. 
A)  3 cm × 5 cm. 
B)  3 cm × 8 cm. 
C)  5 cm × 8 cm. 
D)  Any pair of faces produces the same resistance.

Question 15

A 100-W resistance heater is connected to a 110-V dc source. What current flows through the heater?

Accepted Answer

A)  1.1 A 
B)  2.2 A 
C)  3.3 A 
D)  4.4 A 
E)  0.91 A 
A)  1.1 A 
B)  2.2 A 
C)  3.3 A 
D)  4.4 A 
E)  0.91 A

Question 16

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?

Accepted Answer

A)  resistivity 
B)  resistance 
C)  energy 
D)  current 
E)  capacitance 
A)  resistivity 
B)  resistance 
C)  energy 
D)  current 
E)  capacitance

Question 17

A 5.0-V battery storing 43.0 kJ of energy supplies $1.5 \mathrm {~A}$ of current to a circuit. How much energy does the battery have left after powering the circuit for $1.0 \mathrm {~h} \text { ? }$

Accepted Answer

A)  16 kJ 
B)  27 kJ 
C)  43 kJ 
D)  41 kJ 
A)  16 kJ 
B)  27 kJ 
C)  43 kJ 
D)  41 kJ

Question 18

A light bulb operating at 110 V draws 1.40 A of current. What is its resistance?

Accepted Answer

A)  12.7 Ω 
B)  78.6 Ω 
C)  109 Ω 
D)  154 Ω 
A)  12.7 Ω 
B)  78.6 Ω 
C)  109 Ω 
D)  154 Ω

Question 19

A kilowatt-hour is equivalent to

Accepted Answer

A)  1000 W. 
B)  3600 J. 
C)  3,600,000 J/s. 
D)  3,600,000 J. 
E)  3600 J/s 
A)  1000 W. 
B)  3600 J. 
C)  3,600,000 J/s. 
D)  3,600,000 J. 
E)  3600 J/s

Question 20

The nichrome heating element in an electric drier operates on 240 V and generates heat at the rate of 2.0 kW. The heating element shorts out and, in repairing it, the repairman shortens the nichrome wire by 10%. (Assume the temperature is unchanged. In reality, the resistivity of the wire will depend on its temperature.) What effect will the repair have on the power dissipated in the heating element?

Accepted Answer

A)  The power is still 2.0 kW. 
B)  The power increases to 2.2 kW. 
C)  The power decreases to 1.8 kW. 
D)  None of the given answers is correct. 
A)  The power is still 2.0 kW. 
B)  The power increases to 2.2 kW. 
C)  The power decreases to 1.8 kW. 
D)  None of the given answers is correct.

Exam 22: Current and Resistance

A device with a resistance of 200.0kΩ 200.0 \mathrm{k}{\Omega}200.0kΩ is connected to a 10.0−V10.0 - \mathrm { V }10.0−V battery. How much power does the device use?

A 120-m long metal wire having a resistivity of 1.68 × 10-8 Ω ∙ m has a resistance of 6.0 Ω. What is the diameter of the wire?

The heating element of a toaster is a 5.4-m length of nichrome wire of diameter 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10-6 Ω ∙ m. The toaster is designed to operate at a voltage of 120 V. How much power does it draw in normal operation?

Calculate the current through a 10.0-m long 22-gauge nichrome wire with a radius of 0.321 mm if it is connected across a 12.0-V battery. The resistivity of the nichrome is 1.00 × 10-6 Ω ∙ m.

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?

The figure shows electrons passing through a resistor. The arrow shows the direction in which the electrons are moving. Which of the following statements are correct? (There could be more than one correct choice.)

If a charge of 11.4 C passes through a computer in 1.75 min, what is the average current through the computer?

The power rating of a 400-Ω resistor is 0.25 W. What is the maximum voltage you can safely connect across its ends?

A rod is 4.0 m long and has a square cross-section that is 1.5 cm on each side. An ohmmeter measures 0.040 Ω across its ends. What is the resistivity of the material from which this rod is made?

How much current will be flowing through a 57.0−m57.0 - \mathrm { m }57.0−m length of copper wire with radius 0.0 mm{~mm} mm if it is connected to a source supplying 62.0 V?{~V} ? V? The resistivity of the metal is 1.68 × 10-8 Ω ∙ m.

When the current through a resistor is increased by a factor of 4, the power dissipated by the resistor

If the resistance in a constant voltage circuit is doubled, the power dissipated by that circuit will

You are given a copper bar of dimensions 3 cm × 5 cm × 8 cm and asked to attach leads to it in order to make a resistor. If you want to achieve the largest possible resistance, you should attach the leads to the opposite faces that measure

A 100-W resistance heater is connected to a 110-V dc source. What current flows through the heater?

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?

A 5.0-V battery storing 43.0 kJ of energy supplies 1.5 A1.5 \mathrm {~A}1.5 A of current to a circuit. How much energy does the battery have left after powering the circuit for 1.0 h ? 1.0 \mathrm {~h} \text { ? }1.0 h ?

A light bulb operating at 110 V draws 1.40 A of current. What is its resistance?

A kilowatt-hour is equivalent to

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A device with a resistance of $200.0 \mathrm{k}{\Omega}$ is connected to a $10.0 - \mathrm { V }$ battery. How much power does the device use?

A 120-m long metal wire having a resistivity of 1.68 × 10^-8 Ω ∙ m has a resistance of 6.0 Ω. What is the diameter of the wire?

The heating element of a toaster is a 5.4-m length of nichrome wire of diameter 0.48 mm. The resistivity of nichrome at the operating temperature of the toaster is 1.3 × 10^-6 Ω ∙ m. The toaster is designed to operate at a voltage of 120 V. How much power does it draw in normal operation?

Calculate the current through a 10.0-m long 22-gauge nichrome wire with a radius of 0.321 mm if it is connected across a 12.0-V battery. The resistivity of the nichrome is 1.00 × 10^-6 Ω ∙ m.

How much current will be flowing through a $57.0 - \mathrm { m }$ length of copper wire with radius 0.0 ${~mm}$ if it is connected to a source supplying 62.0 ${~V} ?$ The resistivity of the metal is 1.68 × 10^-8 Ω ∙ m.

A 5.0-V battery storing 43.0 kJ of energy supplies $1.5 \mathrm {~A}$ of current to a circuit. How much energy does the battery have left after powering the circuit for $1.0 \mathrm {~h} \text { ? }$