Question 1

The magnetic field of the Earth is believed responsible for which of the following?

Accepted Answer

A)  deflection of both charged and uncharged cosmic rays 
B)  deflection of charged cosmic rays 
C)  ozone in the upper atmosphere 
D)  solar flares 
A)  deflection of both charged and uncharged cosmic rays 
B)  deflection of charged cosmic rays 
C)  ozone in the upper atmosphere 
D)  solar flares B

Question 2

A proton,which moves perpendicular to a magnetic field of 0.8 T in a circular path of radius 0.062 m,has what speed? (qp = 1.6 × 10−19 C and mp = 1.67 × 10−27 kg)

Accepted Answer

A)  2.9E+5 m/s 
B)  1.3E+7 m/s 
C)  7.4E+6 m/s 
D)  4.8E+6 m/s 
E)  ​1.9E+6 m/s 
A)  2.9E+5 m/s 
B)  1.3E+7 m/s 
C)  7.4E+6 m/s 
D)  4.8E+6 m/s 
E)  ​1.9E+6 m/s D

Question 3

A beam of electrons is sent in the positive x-direction in a region with a uniform magnetic field B in the positive y-direction and a uniform electric field E in the positive z-direction.At which of the following speeds would the electrons be deflected in the positive z-direction?

Accepted Answer

A)  v  E/B 
D)  There is no speed for which this will happen. 
A)  v  E/B 
D)  There is no speed for which this will happen. D

Question 4

A wire is lying horizontally in the north-south direction and the horizontal magnetic field is toward the east.Some positive charges in the wire move north and an equal number of negative charges move south.The direction of the force on the wire will be:

Accepted Answer

A)  east. 
B)  down,into the page. 
C)  up,out of the page. 
D)  There is no magnetic force. 
A)  east. 
B)  down,into the page. 
C)  up,out of the page. 
D)  There is no magnetic force.

Question 5

A solenoid with 338 turns,0.28 m long,carrying a current of 2.6 A and with a radius of 10−2 m will have what strength magnetic field at its center? (magnetic permeability in empty space µ0 = 4π × 10−7 T⋅m/A)

Accepted Answer

A)  5.5E-2 T 
B)  9.9E-4 T 
C)  1.1E-3 T 
D)  3.9E-3 T 
E)  ​1.2E-2 T 
A)  5.5E-2 T 
B)  9.9E-4 T 
C)  1.1E-3 T 
D)  3.9E-3 T 
E)  ​1.2E-2 T

Question 6

Electrical charges and magnetic poles have many similarities,but one difference is:

Accepted Answer

A)  opposite magnetic poles repel. 
B)  one magnetic pole cannot create magnetic poles in other materials. 
C)  a magnetic pole cannot be isolated. 
D)  magnetic poles do not produce magnetic fields. 
A)  opposite magnetic poles repel. 
B)  one magnetic pole cannot create magnetic poles in other materials. 
C)  a magnetic pole cannot be isolated. 
D)  magnetic poles do not produce magnetic fields.

Question 7

There is a magnetic force on a particle.It is possible that the particle is:

Accepted Answer

A)  uncharged. 
B)  stationary. 
C)  moving in the direction of the magnetic field. 
D)  not part of a wire. 
A)  uncharged. 
B)  stationary. 
C)  moving in the direction of the magnetic field. 
D)  not part of a wire.

Question 8

A circular coil (radius = 0.54 m)has 163 turns and is in a uniform magnetic field.If the orientation of the coil is varied through all possible positions,the maximum torque on the coil by magnetic forces is 0.19 N⋅m when the current in the coil is 2.1 mA.What is the magnitude of the magnetic field?

Accepted Answer

A)  1.9 T 
B)  0.05 T 
C)  0.61 T 
D)  53 T 
E)  ​0.99 T 
A)  1.9 T 
B)  0.05 T 
C)  0.61 T 
D)  53 T 
E)  ​0.99 T

Question 9

The dip angle is:

Accepted Answer

A)  another term for magnetic declination. 
B)  a measure of the tendency for a compass to point south. 
C)  close to or at zero near the equator. 
D)  close to or at zero just north of Hudson Bay. 
A)  another term for magnetic declination. 
B)  a measure of the tendency for a compass to point south. 
C)  close to or at zero near the equator. 
D)  close to or at zero just north of Hudson Bay.

Question 10

A current in a solenoid with N turns creates a magnetic field at the center of that loop.The field strength is directly proportional to:

Accepted Answer

A)  number of turns in the loop. 
B)  current strength. 
C)  Both choices A and B are valid. 
D)  None of the above are valid. 
A)  number of turns in the loop. 
B)  current strength. 
C)  Both choices A and B are valid. 
D)  None of the above are valid.

Question 11

A proton is released such that it has an initial speed of 3.7 × 105 m/s from left to right across the page.A magnetic field of 1.5 T is present at an angle of 18° to the horizontal direction (or positive x axis).What is the magnitude of the force experienced by the proton? (qp = 1.6 × 10−19 C)

Accepted Answer

A)  4.4E-33 N 
B)  2.0E-33 N 
C)  2.7E-14 N 
D)  6.7E-14 N 
E)  ​8.4E-14 N 
A)  4.4E-33 N 
B)  2.0E-33 N 
C)  2.7E-14 N 
D)  6.7E-14 N 
E)  ​8.4E-14 N

Question 12

A proton moves across the Earth's equator in a northeasterly direction.At this point the Earth's magnetic field has a direction due north and is parallel to the surface.What is the direction of the force acting on the proton at this instant?

Accepted Answer

A)  toward the northwest 
B)  out of the Earth's surface 
C)  into the Earth's surface 
D)  toward the northeast 
A)  toward the northwest 
B)  out of the Earth's surface 
C)  into the Earth's surface 
D)  toward the northeast

Question 13

Square coil A has 2N turns and sides of length L,and square coil B has N turns and sides of length 2L.When a current of 2 amps is sent through coil A and a current of 1 amp is sent through coil B,which coil has the greater magnetic moment?

Accepted Answer

A)  coil A 
B)  coil B 
C)  Both have the same magnetic moment. 
D)  More information is needed. 
A)  coil A 
B)  coil B 
C)  Both have the same magnetic moment. 
D)  More information is needed.

Question 14

The current in a long wire creates a magnetic field in the region around the wire.How is the strength of the field at distance r from the wire center related to the magnitude of the field?

Accepted Answer

A)  field directly proportional to r 
B)  field inversely proportional to r 
C)  field directly proportional to r2 
D)  field inversely proportional to r2 
A)  field directly proportional to r 
B)  field inversely proportional to r 
C)  field directly proportional to r2 
D)  field inversely proportional to r2

Question 15

At the Fermilab accelerator in Weston,Illinois,singly-charged ions with momentum 4.8 × 10−16 kg⋅m/s are held in a circular orbit of radius 0.8 km by an upward magnetic field.What B-field must be used to maintain the ions in this orbit? (qion = 1.6 × 10−19 C)

Accepted Answer

A)  9.6 T 
B)  2.4 T 
C)  3.8 T 
D)  0.16 T 
E)  ​0.27 T 
A)  9.6 T 
B)  2.4 T 
C)  3.8 T 
D)  0.16 T 
E)  ​0.27 T

Question 16

In a mass spectrometer,an ion will have a smaller radius for its circular path if:

Accepted Answer

A)  its speed is greater. 
B)  its mass is greater. 
C)  its charge is greater. 
D)  the magnetic field is weaker. 
A)  its speed is greater. 
B)  its mass is greater. 
C)  its charge is greater. 
D)  the magnetic field is weaker.

Question 17

A stationary positive charge +Q is located in a magnetic field B,which is directed toward the right as indicated.The direction of the magnetic force on Q is:

Accepted Answer

A)  toward the right. 
B)  up. 
C)  down. 
D)  There is no magnetic force. 
A)  toward the right. 
B)  up. 
C)  down. 
D)  There is no magnetic force.

Question 18

A circular loop carrying a current of 1.6 A is oriented in a magnetic field of 0.28 T.The loop has an area of 0.22 m2 and is mounted on an axis,perpendicular to the magnetic field,which allows the loop to rotate.If the plane of the loop is oriented parallel to the field,what torque is created by the interaction of the loop current and the field?

Accepted Answer

A)  0.04 N⋅m 
B)  0.16 N⋅m 
C)  0.10 N⋅m 
D)  0.049 N⋅m 
E)  ​0.028 N⋅m 
A)  0.04 N⋅m 
B)  0.16 N⋅m 
C)  0.10 N⋅m 
D)  0.049 N⋅m 
E)  ​0.028 N⋅m

Question 19

A high-voltage power line 26.9 m above the ground carries a current of 2722 A.What is the magnetic field due to the current directly underneath the power line? (µ0 = 4π × 10−7 T⋅m/A)

Accepted Answer

A)  20.2 µT 
B)  63.6 µT 
C)  64.4 mT 
D)  12.7 mT 
E)  ​12.7 T 
A)  20.2 µT 
B)  63.6 µT 
C)  64.4 mT 
D)  12.7 mT 
E)  ​12.7 T

Question 20

A superconducting solenoid is to be designed to generate a magnetic field of 6.10 T.If the solenoid winding has 969 turns/m,what is the required current? (µ0 = 4π × 10−7 T⋅m/A)

Accepted Answer

A)  2510 A 
B)  1600 A 
C)  5010 A 
D)  800 A 
E)  ​140 A 
A)  2510 A 
B)  1600 A 
C)  5010 A 
D)  800 A 
E)  ​140 A

Exam 19: Magnetism Magnets

The magnetic field of the Earth is believed responsible for which of the following?

A proton,which moves perpendicular to a magnetic field of 0.8 T in a circular path of radius 0.062 m,has what speed? (qp = 1.6 × 10−19 C and mp = 1.67 × 10−27 kg)

A beam of electrons is sent in the positive x-direction in a region with a uniform magnetic field B in the positive y-direction and a uniform electric field E in the positive z-direction.At which of the following speeds would the electrons be deflected in the positive z-direction?

A wire is lying horizontally in the north-south direction and the horizontal magnetic field is toward the east.Some positive charges in the wire move north and an equal number of negative charges move south.The direction of the force on the wire will be:

A solenoid with 338 turns,0.28 m long,carrying a current of 2.6 A and with a radius of 10−2 m will have what strength magnetic field at its center? (magnetic permeability in empty space µ0 = 4π × 10−7 T⋅m/A)

Electrical charges and magnetic poles have many similarities,but one difference is:

There is a magnetic force on a particle.It is possible that the particle is:

The dip angle is:

A current in a solenoid with N turns creates a magnetic field at the center of that loop.The field strength is directly proportional to:

A proton is released such that it has an initial speed of 3.7 × 105 m/s from left to right across the page.A magnetic field of 1.5 T is present at an angle of 18° to the horizontal direction (or positive x axis).What is the magnitude of the force experienced by the proton? (qp = 1.6 × 10−19 C)

A proton moves across the Earth's equator in a northeasterly direction.At this point the Earth's magnetic field has a direction due north and is parallel to the surface.What is the direction of the force acting on the proton at this instant?

Square coil A has 2N turns and sides of length L,and square coil B has N turns and sides of length 2L.When a current of 2 amps is sent through coil A and a current of 1 amp is sent through coil B,which coil has the greater magnetic moment?

The current in a long wire creates a magnetic field in the region around the wire.How is the strength of the field at distance r from the wire center related to the magnitude of the field?

At the Fermilab accelerator in Weston,Illinois,singly-charged ions with momentum 4.8 × 10−16 kg⋅m/s are held in a circular orbit of radius 0.8 km by an upward magnetic field.What B-field must be used to maintain the ions in this orbit? (qion = 1.6 × 10−19 C)

In a mass spectrometer,an ion will have a smaller radius for its circular path if:

A stationary positive charge +Q is located in a magnetic field B,which is directed toward the right as indicated.The direction of the magnetic force on Q is:

A high-voltage power line 26.9 m above the ground carries a current of 2722 A.What is the magnetic field due to the current directly underneath the power line? (µ0 = 4π × 10−7 T⋅m/A)

A superconducting solenoid is to be designed to generate a magnetic field of 6.10 T.If the solenoid winding has 969 turns/m,what is the required current? (µ0 = 4π × 10−7 T⋅m/A)

Introduction

Introduction: Part A

Motion in One Dimension

Motion in One Dimension: Part A

Vectors and Two-Dimensional Motion

Vectors and Two-Dimensional Motion: Part A

The Laws of Motion

The Laws of Motion: Part A

Energy

Energy: Part A

Momentum and Collisions

Momentum and Collisions: Part A

Rotational Motion and the Law of Gravity

Rotational Motion and the Law of Gravity: Part A

Rotational Equilibrium and Rotational Dynamics

Rotational Equilibrium and Rotational Dynamics: Part A

Solids and Fluids

Solids and Fluids: Part A

Thermal Physics

Thermal Physics: Part A

Energy in Thermal Processes Heat and Internal Energy

Energy in Thermal Processes Heat and Internal Energy: Part A

The Laws of Thermodynamics Work in Thermodynamic Processes

The Laws of Thermodynamics Work in Thermodynamic Processes: Part A

Vibrations and Waves

Vibrations and Waves: Part A

Sound

Sound: Part A

Electric Forces and Electric Fields

Electric Forces and Electric Fields: Part A

Electrical Energy and Capacitance

Electrical Energy and Capacitance: Part A

Current and Resistance Electric Current

Current and Resistance Electric Current: Part A

Direct-Current Circuits Sources of EMF

Direct-Current Circuits Sources of EMF: Part A

Magnetism Magnets: Part A

Induced Voltages and Inductance

Induced Voltages and Inductance: Part A

Alternating-Current Circuits and Electromagnetic Waves

Alternating-Current Circuits and Electromagnetic Waves: Part A

Reflection and Refraction of Light

Reflection and Refraction of Light: Part A

Mirrors and Lenses

Mirrors and Lenses: Part A

Wave Optics

Wave Optics: Part A

Optical Instruments

Optical Instruments: Part A

Relativity

Relativity: Part A

Quantum Physics Blackbody Radiation and Plancks Hypothesis

Quantum Physics Blackbody Radiation and Plancks Hypothesis: Part A

Atomic Physics

Atomic Physics: Part A

Nuclear Physics

Nuclear Physics: Part A

Nuclear Energy and Elementary Particles

Nuclear Energy and Elementary Particles: Part A

Particle Collisions, Mediating Photons, and Quark Structures: Exploring the Fundamentals of Physics

Filters

A proton,which moves perpendicular to a magnetic field of 0.8 T in a circular path of radius 0.062 m,has what speed? (q_p = 1.6 × 10−¹⁹ C and m_p = 1.67 × 10−²⁷ kg)

A solenoid with 338 turns,0.28 m long,carrying a current of 2.6 A and with a radius of 10−² m will have what strength magnetic field at its center? (magnetic permeability in empty space µ₀ = 4π × 10−⁷ T⋅m/A)

At the Fermilab accelerator in Weston,Illinois,singly-charged ions with momentum 4.8 × 10−¹⁶ kg⋅m/s are held in a circular orbit of radius 0.8 km by an upward magnetic field.What B-field must be used to maintain the ions in this orbit? (qion = 1.6 × 10−¹⁹ C)

A high-voltage power line 26.9 m above the ground carries a current of 2722 A.What is the magnetic field due to the current directly underneath the power line? (µ₀ = 4π × 10−⁷ T⋅m/A)

A superconducting solenoid is to be designed to generate a magnetic field of 6.10 T.If the solenoid winding has 969 turns/m,what is the required current? (µ₀ = 4π × 10−⁷ T⋅m/A)