Question 1

A 25-W soldering iron runs on 110 V dc.What is its resistance?

Accepted Answer

A) 0.0020 Ω 
B) 4.4 Ω 
C) 0.48 kΩ 
D) 2.8 kΩ 
A) 0.0020 Ω 
B) 4.4 Ω 
C) 0.48 kΩ 
D) 2.8 kΩ

Question 2

When a 14.0-A current flows through an 8.00-Ω device for 24.0 hours,how much does this cost if energy costs $0.0900 per kW ∙ h?

Accepted Answer

A) $0.24 
B) $1.04 
C) $2.16 
D) $3.39 
A) $0.24 
B) $1.04 
C) $2.16 
D) $3.39

Question 3

The length of a certain wire is doubled and at the same time its radius is reduced by a factor of 2.What is the new resistance of this wire?

Accepted Answer

A) It is 2 times as large. 
B) It is 4 times as large. 
C) It is 6 times as large. 
D) It it 8 times as large. 
E) It is 1/2 as large. 
A) It is 2 times as large. 
B) It is 4 times as large. 
C) It is 6 times as large. 
D) It it 8 times as large. 
E) It is 1/2 as large.

Question 4

A combination of a 2.0-Ω resistor in series with 4.0-Ω resistor is connected in parallel with a 3.0-Ω resistor.What is the equivalent resistance of this system?

Accepted Answer

A) 2.0 Ω 
B) 3.0 Ω 
C) 4.0 Ω 
D) 9.0 Ω 
A) 2.0 Ω 
B) 3.0 Ω 
C) 4.0 Ω 
D) 9.0 Ω

Question 5

A 150-W light bulb is designed to operate at 110 V dc.How much current does it draw?

Accepted Answer

A) 0.73 A 
B) 1.4 A 
C) 2.0 A 
D) 15 A 
A) 0.73 A 
B) 1.4 A 
C) 2.0 A 
D) 15 A

Question 6

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 7

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 8

A15-Ω resistor is connected in parallel with a 30-Ω resistor.If this combination is now connected in series with an ideal 9.0-V battery and a 20-Ω resistor,what is the current through the 15-Ω resistor?

Accepted Answer

A) 0.10 A 
B) 0.13 A 
C) 0.20 A 
D) 0.26 A 
A) 0.10 A 
B) 0.13 A 
C) 0.20 A 
D) 0.26 A

Question 9

If the length and diameter of a wire of circular cross section are both tripled,the resistance will be

Accepted Answer

A) unchanged. 
B) tripled. 
C) increased by a factor of 9. 
D) 1/3 of what it originally was. 
E) 1/9 of what it originally was. 
A) unchanged. 
B) tripled. 
C) increased by a factor of 9. 
D) 1/3 of what it originally was. 
E) 1/9 of what it originally was.

Question 10

How much energy does a 100-W light bulb use in 8.0 hours?

Accepted Answer

A) 0.0080 kWh 
B) 0.80 kWh 
C) 13 kWh 
D) 800 kWh 
A) 0.0080 kWh 
B) 0.80 kWh 
C) 13 kWh 
D) 800 kWh

Question 11

A current of 5.0 A flows through an electrical device for 10 seconds.How many electrons flow through this device during this time? (e = 1.60 × 10-19 C)

Accepted Answer

A) 0.20 
B) 20 
C) 2.0 
D) 3.1 ×   
E) 31 ×   
A) 0.20 
B) 20 
C) 2.0 
D) 3.1 ×   
E) 31 ×

Question 12

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 13

Determine the current in the 18-Ω resistor for the circuit shown in the figure assuming that the batteries are ideal.

Accepted Answer

A) 0.25 A 
B) 0.50 A 
C) 0.75 A 
D) 1.0 A 
A) 0.25 A 
B) 0.50 A 
C) 0.75 A 
D) 1.0 A

Question 14

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 15

A 5.0-μF and a 12.0-μF capacitor are connected in series,and the series arrangement is connected in parallel to a 29.0-μF. Capacitor.How much capacitance would a single capacitor need to replace this combination of three capacitors?

Accepted Answer

A) 33 μF 
B) 13 μF 
C) 16 μF 
D) 38 μF 
A) 33 μF 
B) 13 μF 
C) 16 μF 
D) 38 μF

Question 16

Consider two copper wires of equal cross-sectional area.One wire has 3 times the length of the other.How do the resistivities of these two wires compare?

Accepted Answer

A) Both wires have the same resistivity. 
B) The longer wire has 3 times the resistivity of the shorter wire. 
C) The longer wire has 9 times times the resistivity of the shorter wire. 
D) The longer wire has 27 times times the resistivity of the shorter wire. 
A) Both wires have the same resistivity. 
B) The longer wire has 3 times the resistivity of the shorter wire. 
C) The longer wire has 9 times times the resistivity of the shorter wire. 
D) The longer wire has 27 times times the resistivity of the shorter wire.

Question 17

Determine the current in the 8.0-Ω resistor for the circuit shown in the figure.Assume that the batteries are ideal and that all numbers are accurate to two significant figures.

Accepted Answer

A) 0.28 A 
B) 1.3 A 
C) 1.6 A 
D) 2.1 A 
A) 0.28 A 
B) 1.3 A 
C) 1.6 A 
D) 2.1 A

Question 18

The following three appliances are connected in parallel across an ideal 120-V dc power source: 1200-W toaster,650-W coffee pot,and 600-W microwave.If all were operated at the same time what total current would they draw from the source?

Accepted Answer

A) 4.0 A 
B) 5.0 A 
C) 10 A 
D) 20 A 
A) 4.0 A 
B) 5.0 A 
C) 10 A 
D) 20 A

Question 19

What is the magnitude of the potential difference between points C and D for the circuit shown in the figure? The battery is ideal,and all the numbers are accurate to two significant figures.

Accepted Answer

A) 6.0 V 
B) 4.0 V 
C) 3.0 V 
D) 2.0 V 
A) 6.0 V 
B) 4.0 V 
C) 3.0 V 
D) 2.0 V

Question 20

A group of 1.0-μF,2.0-μF,and 3.0-μF capacitors is connected in parallel across a 24-V potential difference (a battery).How much energy is stored in this three-capacitor combination when the capacitors are fully charged?

Accepted Answer

A) 1.7 mJ 
B) 2.1 mJ 
C) 4.8 mJ 
D) 7.1 mJ 
A) 1.7 mJ 
B) 2.1 mJ 
C) 4.8 mJ 
D) 7.1 mJ

Exam 21: Electric Current and Direct-Current Circuits

A 25-W soldering iron runs on 110 V dc.What is its resistance?

When a 14.0-A current flows through an 8.00-Ω device for 24.0 hours,how much does this cost if energy costs $0.0900 per kW ∙ h?

The length of a certain wire is doubled and at the same time its radius is reduced by a factor of 2.What is the new resistance of this wire?

A combination of a 2.0-Ω resistor in series with 4.0-Ω resistor is connected in parallel with a 3.0-Ω resistor.What is the equivalent resistance of this system?

A 150-W light bulb is designed to operate at 110 V dc.How much current does it draw?

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?

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

A15-Ω resistor is connected in parallel with a 30-Ω resistor.If this combination is now connected in series with an ideal 9.0-V battery and a 20-Ω resistor,what is the current through the 15-Ω resistor?

If the length and diameter of a wire of circular cross section are both tripled,the resistance will be

How much energy does a 100-W light bulb use in 8.0 hours?

A current of 5.0 A flows through an electrical device for 10 seconds.How many electrons flow through this device during this time? (e = 1.60 × 10-19 C)

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.

Determine the current in the 18-Ω resistor for the circuit shown in the figure assuming that the batteries are ideal.

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. )

A 5.0-μF and a 12.0-μF capacitor are connected in series,and the series arrangement is connected in parallel to a 29.0-μF. Capacitor.How much capacitance would a single capacitor need to replace this combination of three capacitors?

Consider two copper wires of equal cross-sectional area.One wire has 3 times the length of the other.How do the resistivities of these two wires compare?

Determine the current in the 8.0-Ω resistor for the circuit shown in the figure.Assume that the batteries are ideal and that all numbers are accurate to two significant figures.

The following three appliances are connected in parallel across an ideal 120-V dc power source: 1200-W toaster,650-W coffee pot,and 600-W microwave.If all were operated at the same time what total current would they draw from the source?

What is the magnitude of the potential difference between points C and D for the circuit shown in the figure? The battery is ideal,and all the numbers are accurate to two significant figures.

A group of 1.0-μF,2.0-μF,and 3.0-μF capacitors is connected in parallel across a 24-V potential difference (a battery).How much energy is stored in this three-capacitor combination when the capacitors are fully charged?

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic Energy

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Waves and Sound

Fluids

Temperature and Heat

Phases and Phase Changes

The Laws of Thermodynamics

Electric Charges, Forces, and Fields

Electric Potential and Electric

Magnetism

Magnetic Flux and Faradays Law of Induction

Alternating-Current Circuits

Electromagnetic Waves

Geometrical Optics

Optical Instruments

Physical Optics: Interference and Diffraction

Relativity

Quantum Physics

Atomic Physics

Nuclear Physics and Nuclear Radiation

Filters

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?

A current of 5.0 A flows through an electrical device for 10 seconds.How many electrons flow through this device during this time? (e = 1.60 × 10^-19C)

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.