Question 1

Which one of the following statements is correct?

Accepted Answer

A) Earth's geographic north pole is the north pole of Earth's magnetic field. 
B) Earth's geographic south pole is the south pole of Earth's magnetic field. 
C) The north pole of a magnet points towards Earth's geographic north pole. 
D) The north pole of a magnet points towards Earth's geographic south pole. 
E) None of the above statements is correct. 
A) Earth's geographic north pole is the north pole of Earth's magnetic field. 
B) Earth's geographic south pole is the south pole of Earth's magnetic field. 
C) The north pole of a magnet points towards Earth's geographic north pole. 
D) The north pole of a magnet points towards Earth's geographic south pole. 
E) None of the above statements is correct.

Question 2

The $\vec { B }$ field due to the current through a long,straight wire is 8.0 μT at a distance of 4.0 cm from the center of the wire.What is the current in the wire? (μ0 = 4π × 10-7 T ∙ m/A)

Accepted Answer

A) 0.20 A 
B) 0.40 A 
C) 0.80 A 
D) 3.2 A 
E) 1.6 A 
A) 0.20 A 
B) 0.40 A 
C) 0.80 A 
D) 3.2 A 
E) 1.6 A

Question 3

A charged particle moves with a constant speed through a region where a uniform magnetic field is present.If the $\vec { B }$ field points straight upward,the magnetic force exerted on this particle will be strongest when the particle moves

Accepted Answer

A) straight upward. 
B) straight downward. 
C) in a plane parallel to Earth's surface. 
D) upward at an angle of 45° above the horizontal. 
A) straight upward. 
B) straight downward. 
C) in a plane parallel to Earth's surface. 
D) upward at an angle of 45° above the horizontal.

Question 4

When a charged particle is moving in a static uniform magnetic field

Accepted Answer

A) there will always be a magnetic force exerted on it, regardless of its direction of motion. 
B) there may be a magnetic force exerted on it which will cause its speed to change. 
C) there may be a magnetic force exerted on it, but its speed will not change. 
D) there may be a magnetic force exerted on it, but its direction of motion will not change. 
E) None of the above statements are true. 
A) there will always be a magnetic force exerted on it, regardless of its direction of motion. 
B) there may be a magnetic force exerted on it which will cause its speed to change. 
C) there may be a magnetic force exerted on it, but its speed will not change. 
D) there may be a magnetic force exerted on it, but its direction of motion will not change. 
E) None of the above statements are true.

Question 5

The $\vec { B }$ field at point P due to a 2.0-A current through a long,straight,thin wire is 8.0 μT.How far is point P from the wire? (μ0 = 4π × 10-7 T ∙ m/A)

Accepted Answer

A) 2.0 cm 
B) 2.5 cm 
C) 4.0 cm 
D) 5.0 cm 
E) 10 cm 
A) 2.0 cm 
B) 2.5 cm 
C) 4.0 cm 
D) 5.0 cm 
E) 10 cm

Question 6

A thin copper rod 1.0 m long has a mass of 0.050 kg and is in a $\vec { B }$ field of 0.10 T.What minimum current in the rod is needed in order for the magnetic force to balance the force exerted on the rod by Earth?

Accepted Answer

A) 1.2 A 
B) 2.5 A 
C) 4.9 A 
D) 9.8 A 
A) 1.2 A 
B) 2.5 A 
C) 4.9 A 
D) 9.8 A

Question 7

An electron moves with a speed of 3.0 × 104 m/s perpendicular to a uniform magnetic field of 0.40 T.What is the magnitude of the magnetic force exerted on the electron? (e = 1.60 × 10-19C)

Accepted Answer

A) 4.8 × 10-14 N 
B) 1.9 × 10-15 N 
C) 5 × 10-20 N 
D) 2.2 × 10-24 N 
A) 4.8 × 10-14 N 
B) 1.9 × 10-15 N 
C) 5 × 10-20 N 
D) 2.2 × 10-24 N

Question 8

Which one of the following statements is correct?

Accepted Answer

A) When a current-carrying wire is in your right hand, with your thumb in the direction of the current, your fingers point opposite to the direction of the $\vec { B }$ field lines. 
B) When a current-carrying wire is in your right hand, with your thumb in the direction of the current, your fingers point in the direction of the $\vec { B }$ field lines. 
C) When a current-carrying wire is in your left hand, with your thumb in the direction of the current, your fingers point in the direction of the $\vec { B }$ field lines. 
A) When a current-carrying wire is in your right hand, with your thumb in the direction of the current, your fingers point opposite to the direction of the $\vec { B }$ field lines. 
B) When a current-carrying wire is in your right hand, with your thumb in the direction of the current, your fingers point in the direction of the $\vec { B }$ field lines. 
C) When a current-carrying wire is in your left hand, with your thumb in the direction of the current, your fingers point in the direction of the $\vec { B }$ field lines.

Question 9

A wire lying in the plane of the page carries a current toward the bottom of the page,as shown in the figure.What is the direction of the magnetic force it exerts on an electron that is moving to the left directly toward the wire,as shown?

Accepted Answer

A) straight into the page 
B) straight out of the page 
C) directly toward the top of the page 
D) directly toward the bottom of the page 
E) directly to the left away from the wire 
A) straight into the page 
B) straight out of the page 
C) directly toward the top of the page 
D) directly toward the bottom of the page 
E) directly to the left away from the wire

Question 10

If a calculated quantity has units of $\frac { \mathrm { N } \cdot \mathrm { s } } { \mathrm { C } \cdot \mathrm { m } }$ ,that quantity could be

Accepted Answer

A) an $\vec { E }$ field. 
B) an electric potential. 
C) μ0. 
D) a $\vec { B }$ field. 
E) a magnetic torque. 
A) an $\vec { E }$ field. 
B) an electric potential. 
C) μ0. 
D) a $\vec { B }$ field. 
E) a magnetic torque.

Question 11

An electron traveling toward the magnetic north with speed 400 km/s enters a region where Earth's $\vec { B }$ field has the magnitude 5.0 × 10-5 T and is directed downward at 45° below horizontal.What magnitude magnetic force is exerted on the electron? (e = 1.60 × 10-19C)

Accepted Answer

Question 12

In the figure,the two long straight wires are separated by a distance of $d = 0.40 \mathrm {~m}$ The currents are $I_1$ = 1.0 A to the right in the upper wire and $I _2$ = 8.0 A to the left in the lower wire.What are the magnitude and direction of the $\vec { B }$ field at point P,that is a distance $d / 2 = 0.20 \mathrm {~m}$ below the lower wire? (μ0 = 4π × 10-7 T ∙ m/A)

Accepted Answer

Question 13

A proton moving with a velocity of 4.0 × 104 m/s enters a magnetic field of 0.20 T.If the angle between the velocity of the proton and the direction of the $\vec { B }$ field is 60°,what is the magnitude of the magnetic force exerted on the proton? (e = 1.60 × 10-19C)

Accepted Answer

A) 1.8 × 10-15 N 
B) 0.60 × 10-15 N 
C) 1.1 × 10-15 N 
D) 2.2 × 10-15 N 
A) 1.8 × 10-15 N 
B) 0.60 × 10-15 N 
C) 1.1 × 10-15 N 
D) 2.2 × 10-15 N

Question 14

After landing on an unexplored Klingon planet,Mr.Spock investigates the direction of the magnetic field by firing a beam of electrons in various directions and by recording the following observations: A magnetic force in the northwest direction is exerted on the clectrons moving upward.
Electrons moving horizontally toward the north are pushed downward.
Electrons moving horizontally toward the southeast are pushed upward.
Mr.Spock therefore concludes that the $\vec { B }$ field at this landing site is in which direction?

Accepted Answer

A) toward the east 
B) toward the northeast 
C) toward the southwest 
D) toward the southeast 
E) toward the west 
A) toward the east 
B) toward the northeast 
C) toward the southwest 
D) toward the southeast 
E) toward the west

Question 15

A flat coil containing 25 identical loops carries 6.4 A of current.When it is placed in a uniform magnetic field of 0.22 T that is oriented parallel to the plane of the coil,the magnetic torque on it is 3.7 N ∙ m.
(a)What is the magnetic moment of the coil?
(b)What is the area of each loop?

Accepted Answer

(a)17 A ∙

Question 16

The $\vec { B }$ field at a distance of 2 cm from a long straight current-carrying wire is 4 μT.What is the $\vec { B }$ field at a distance of 1 cm from this wire?

Accepted Answer

A) 2 μT 
B) 4 μT 
C) 6 μT 
D) 8 μT 
E) 10 μT 
A) 2 μT 
B) 4 μT 
C) 6 μT 
D) 8 μT 
E) 10 μT

Question 17

A flat circular wire loop lies in a horizontal plane on a table and carries current in a counterclockwise direction when viewed from above.At this point,Earth's $\vec { B }$ field points to the north and dips below the horizontal.Which side of the coil tends to lift off of the table due to the magnetic torque on the loop?

Accepted Answer

A) the north side 
B) the east side 
C) the south side 
D) the west side 
E) The entire loop lifts straight up. 
A) the north side 
B) the east side 
C) the south side 
D) the west side 
E) The entire loop lifts straight up.

Question 18

A long,straight,horizontal wire carries current toward the east.An electron moves toward the east alongside and just south of the wire.What is the direction of the magnetic force exerted on the electron?

Accepted Answer

A) toward the north 
B) toward the south 
C) upward 
D) downward 
E) toward the west. 
A) toward the north 
B) toward the south 
C) upward 
D) downward 
E) toward the west.

Question 19

A proton,moving in a uniform magnetic field,moves in a circle perpendicular to the $\vec { B }$ field lines and takes time T for each circle.If the proton's speed tripled,what would now be its time to go around each circle?

Accepted Answer

A) 9T 
B) 3T 
C) T 
D) T/3 
E) T/9 
A) 9T 
B) 3T 
C) T 
D) T/3 
E) T/9

Question 20

A charged particle moving along the +x-axis enters a uniform $\vec { B }$ field pointing along the +z-axis.A uniform electric field is also present.Due to the combined effect of both fields,the particle does not change its velocity.What is the direction of the electric field?

Accepted Answer

A) along the -y-axis 
B) along the +y-axis 
C) along the -x-axis 
D) along the +x-axis 
E) along the -z-axis 
A) along the -y-axis 
B) along the +y-axis 
C) along the -x-axis 
D) along the +x-axis 
E) along the -z-axis

Exam 18: Magnetism

Which one of the following statements is correct?

The B⃗\vec { B }B field due to the current through a long,straight wire is 8.0 μT at a distance of 4.0 cm from the center of the wire.What is the current in the wire? (μ0 = 4π × 10-7 T ∙ m/A)

A charged particle moves with a constant speed through a region where a uniform magnetic field is present.If the B⃗\vec { B }B field points straight upward,the magnetic force exerted on this particle will be strongest when the particle moves

When a charged particle is moving in a static uniform magnetic field

The B⃗\vec { B }B field at point P due to a 2.0-A current through a long,straight,thin wire is 8.0 μT.How far is point P from the wire? (μ0 = 4π × 10-7 T ∙ m/A)

A thin copper rod 1.0 m long has a mass of 0.050 kg and is in a B⃗\vec { B }B field of 0.10 T.What minimum current in the rod is needed in order for the magnetic force to balance the force exerted on the rod by Earth?

An electron moves with a speed of 3.0 × 104 m/s perpendicular to a uniform magnetic field of 0.40 T.What is the magnitude of the magnetic force exerted on the electron? (e = 1.60 × 10-19C)

Which one of the following statements is correct?

A wire lying in the plane of the page carries a current toward the bottom of the page,as shown in the figure.What is the direction of the magnetic force it exerts on an electron that is moving to the left directly toward the wire,as shown?

If a calculated quantity has units of N⋅sC⋅m\frac { \mathrm { N } \cdot \mathrm { s } } { \mathrm { C } \cdot \mathrm { m } }C⋅mN⋅s​ ,that quantity could be

An electron traveling toward the magnetic north with speed 400 km/s enters a region where Earth's B⃗\vec { B }B field has the magnitude 5.0 × 10-5 T and is directed downward at 45° below horizontal.What magnitude magnetic force is exerted on the electron? (e = 1.60 × 10-19C)

A proton moving with a velocity of 4.0 × 104 m/s enters a magnetic field of 0.20 T.If the angle between the velocity of the proton and the direction of the B⃗\vec { B }B field is 60°,what is the magnitude of the magnetic force exerted on the proton? (e = 1.60 × 10-19C)

A flat coil containing 25 identical loops carries 6.4 A of current.When it is placed in a uniform magnetic field of 0.22 T that is oriented parallel to the plane of the coil,the magnetic torque on it is 3.7 N ∙ m. (a)What is the magnetic moment of the coil? (b)What is the area of each loop?

The B⃗\vec { B }B field at a distance of 2 cm from a long straight current-carrying wire is 4 μT.What is the B⃗\vec { B }B field at a distance of 1 cm from this wire?

A long,straight,horizontal wire carries current toward the east.An electron moves toward the east alongside and just south of the wire.What is the direction of the magnetic force exerted on the electron?

A proton,moving in a uniform magnetic field,moves in a circle perpendicular to the B⃗\vec { B }B field lines and takes time T for each circle.If the proton's speed tripled,what would now be its time to go around each circle?

A charged particle moving along the +x-axis enters a uniform B⃗\vec { B }B field pointing along the +z-axis.A uniform electric field is also present.Due to the combined effect of both fields,the particle does not change its velocity.What is the direction of the electric field?

Introduction

Kinematics: Motion in One Dimension

Newtonian Mechanics

Applying Newtons Laws

Circular Motion

Impulse and Linear Momentum

Work and Energy

Extended Bodies at Rest

Rotational Motion

Gases

Static Fluids

Fluids in Motion

First Law of Thermodynamics

Second Law of Thermodynamics

Electric Charge force and Energy

The Electric Field

Dc Circuits

Electromagnetic Induction

Vibrational Motion

Mechanical Waves

Reflection and Refraction

Mirrors and Lenses

Wave Optics

Electromagnetic Waves

Special Relativity

Quantum Optics

Atomic Physics

Nuclear Physics

Particle Physics

Filters

The $\vec { B }$ field due to the current through a long,straight wire is 8.0 μT at a distance of 4.0 cm from the center of the wire.What is the current in the wire? (μ₀ = 4π × 10^-7 T ∙ m/A)

A charged particle moves with a constant speed through a region where a uniform magnetic field is present.If the $\vec { B }$ field points straight upward,the magnetic force exerted on this particle will be strongest when the particle moves

The $\vec { B }$ field at point P due to a 2.0-A current through a long,straight,thin wire is 8.0 μT.How far is point P from the wire? (μ₀ = 4π × 10^-7 T ∙ m/A)

A thin copper rod 1.0 m long has a mass of 0.050 kg and is in a $\vec { B }$ field of 0.10 T.What minimum current in the rod is needed in order for the magnetic force to balance the force exerted on the rod by Earth?

An electron moves with a speed of 3.0 × 10⁴ m/s perpendicular to a uniform magnetic field of 0.40 T.What is the magnitude of the magnetic force exerted on the electron? (e = 1.60 × 10^-19C)

If a calculated quantity has units of $\frac { \mathrm { N } \cdot \mathrm { s } } { \mathrm { C } \cdot \mathrm { m } }$ ,that quantity could be

An electron traveling toward the magnetic north with speed 400 km/s enters a region where Earth's $\vec { B }$ field has the magnitude 5.0 × 10^-5 T and is directed downward at 45° below horizontal.What magnitude magnetic force is exerted on the electron? (e = 1.60 × 10^-19C)

A proton moving with a velocity of 4.0 × 10⁴ m/s enters a magnetic field of 0.20 T.If the angle between the velocity of the proton and the direction of the $\vec { B }$ field is 60°,what is the magnitude of the magnetic force exerted on the proton? (e = 1.60 × 10^-19C)

The $\vec { B }$ field at a distance of 2 cm from a long straight current-carrying wire is 4 μT.What is the $\vec { B }$ field at a distance of 1 cm from this wire?

A proton,moving in a uniform magnetic field,moves in a circle perpendicular to the $\vec { B }$ field lines and takes time T for each circle.If the proton's speed tripled,what would now be its time to go around each circle?

A charged particle moving along the +x-axis enters a uniform $\vec { B }$ field pointing along the +z-axis.A uniform electric field is also present.Due to the combined effect of both fields,the particle does not change its velocity.What is the direction of the electric field?