Question 1

The magnetic field lines inside a bar magnet go in what direction?

Accepted Answer

A)  from south pole to north pole 
B)  from north pole to south pole 
C)  from side to side 
D)  There are no magnetic field lines inside a bar magnet. 
A)  from south pole to north pole 
B)  from north pole to south pole 
C)  from side to side 
D)  There are no magnetic field lines inside a bar magnet.

Question 2

What current is necessary to generate a field of 0.20 T inside a solenoid with 300 turns per cm?

Accepted Answer

A)  530 A 
B)  5.3 A 
C)  33 A 
D)  0.33 A 
E)  3.1 A 
A)  530 A 
B)  5.3 A 
C)  33 A 
D)  0.33 A 
E)  3.1 A

Question 3

A cyclotron with a magnetic field of 1.2 T is used to accelerate protons. How does the time for the protons to complete one orbit change when the radius of their orbit changes from 10 cm to 22 cm?

Accepted Answer

A)  It increases by a factor of 2.2. 
B)  It decreases by a factor of 2.2. 
C)  It increases by a factor of 4.8. 
D)  It decreases by a factor of 4.8. 
E)  It stays the same. 
A)  It increases by a factor of 2.2. 
B)  It decreases by a factor of 2.2. 
C)  It increases by a factor of 4.8. 
D)  It decreases by a factor of 4.8. 
E)  It stays the same.

Question 4

A proton cyclotron has a magnetic field of 0.20 T between its poles and a radius of 0.40 m. What is the maximum energy for the protons from this machine?

Accepted Answer

A)  1.6 × 10−13 J 
B)  3.2 × 10−13 J 
C)  4.9 × 10−13 J 
D)  3.2 × 10−14 J 
E)  4.9 × 10−14 J 
A)  1.6 × 10−13 J 
B)  3.2 × 10−13 J 
C)  4.9 × 10−13 J 
D)  3.2 × 10−14 J 
E)  4.9 × 10−14 J

Question 5

A coil of 150 turns of wire is in the form of a circle of radius 7.5 cm and sits in the center of a region of uniform magnetic field of strength 1.5 T. The torque on the coil has a maximum value of 0.25 N·m. What is the current in the coils?

Accepted Answer

A)  9.4 A 
B)  200 mA 
C)  4.7 mA 
D)  63 mA 
E)  94 mA 
A)  9.4 A 
B)  200 mA 
C)  4.7 mA 
D)  63 mA 
E)  94 mA

Question 6

A 300-turn coil of area 25 cm2 is placed in an 80 mT magnetic field. If the coil carries a current of 3.3 A, what is the magnitude of the maximum magnetic torque it could experience?

Accepted Answer

A)  20 N·m 
B)  6.0 N·m 
C)  0.13 N·m 
D)  0.20 N·m 
E)  0.060 N·m 
A)  20 N·m 
B)  6.0 N·m 
C)  0.13 N·m 
D)  0.20 N·m 
E)  0.060 N·m

Question 7

A 2.5 cm-long horizontal wire segment has a mass of 0.15 g and carries a current sufficiently large that it levitates when the segment is in a region of uniform B field of magnitude 1.5 T. Assume that the B field is horizontal and perpendicular to the wire segment. The current is passed to the segment by way of massless electrical leads. What is the magnitude of the current in the wire?

Accepted Answer

A)  39 mA 
B)  25 A 
C)  4.0 mA 
D)  Not enough information is given. 
A)  39 mA 
B)  25 A 
C)  4.0 mA 
D)  Not enough information is given.

Question 8

An electric field perpendicular to a magnetic field is used as a velocity selector for Li+ ions, selecting the velocity v1. Next, Li++ ions are sent through the same velocity selector, selecting velocity v2. If neither the electric nor magnetic fields have changed between the two processes, how do v1 and v2 compare?

Accepted Answer

A)  v2 = v1 
B)  v2 = 2 v1 
C)  v2 = v1/2 
D)  v2 = 4 v1 
E)  v2 = v1/4 
A)  v2 = v1 
B)  v2 = 2 v1 
C)  v2 = v1/2 
D)  v2 = 4 v1 
E)  v2 = v1/4

The magnetic field lines inside a bar magnet go in what direction?

What current is necessary to generate a field of 0.20 T inside a solenoid with 300 turns per cm?

A cyclotron with a magnetic field of 1.2 T is used to accelerate protons. How does the time for the protons to complete one orbit change when the radius of their orbit changes from 10 cm to 22 cm?

A proton cyclotron has a magnetic field of 0.20 T between its poles and a radius of 0.40 m. What is the maximum energy for the protons from this machine?

A coil of 150 turns of wire is in the form of a circle of radius 7.5 cm and sits in the center of a region of uniform magnetic field of strength 1.5 T. The torque on the coil has a maximum value of 0.25 N·m. What is the current in the coils?

A 300-turn coil of area 25 cm² is placed in an 80 mT magnetic field. If the coil carries a current of 3.3 A, what is the magnitude of the maximum magnetic torque it could experience?

Introduction

Motion Along a Line

Motion in a Plane

Force and Newtons Laws of Motion

Circular Motion

Conservation of Energy

Linear Momentum

Torque and Angular Momentum

Fluids

Elasticity and Oscillations

Waves

Sound

Temperature and the Ideal Gas

Heat

Thermodynamics

Electric Forces and Fields

Electric Potential

Electric Current and Circuits

Electromagnetic Induction

Alternating Current

Electromagnetic Waves

Reflection and Refraction of Light

Optical Instruments

Interference and Diffraction

Relativity

Early Quantum Physics and the Photon

Quantum Physics

Nuclear Physics

Particle Physics

Filters

Exam 19: Magnetic Forces and Fields

The magnetic field lines inside a bar magnet go in what direction?

What current is necessary to generate a field of 0.20 T inside a solenoid with 300 turns per cm?

A cyclotron with a magnetic field of 1.2 T is used to accelerate protons. How does the time for the protons to complete one orbit change when the radius of their orbit changes from 10 cm to 22 cm?

A proton cyclotron has a magnetic field of 0.20 T between its poles and a radius of 0.40 m. What is the maximum energy for the protons from this machine?

A coil of 150 turns of wire is in the form of a circle of radius 7.5 cm and sits in the center of a region of uniform magnetic field of strength 1.5 T. The torque on the coil has a maximum value of 0.25 N·m. What is the current in the coils?

A 300-turn coil of area 25 cm2 is placed in an 80 mT magnetic field. If the coil carries a current of 3.3 A, what is the magnitude of the maximum magnetic torque it could experience?

Introduction

Motion Along a Line

Motion in a Plane

Force and Newtons Laws of Motion

Circular Motion

Conservation of Energy

Linear Momentum

Torque and Angular Momentum

Fluids

Elasticity and Oscillations

Waves

Sound

Temperature and the Ideal Gas

Heat

Thermodynamics

Electric Forces and Fields

Electric Potential

Electric Current and Circuits

Electromagnetic Induction

Alternating Current

Electromagnetic Waves

Reflection and Refraction of Light

Optical Instruments

Interference and Diffraction

Relativity

Early Quantum Physics and the Photon

Quantum Physics

Nuclear Physics

Particle Physics

Filters

A 300-turn coil of area 25 cm² is placed in an 80 mT magnetic field. If the coil carries a current of 3.3 A, what is the magnitude of the maximum magnetic torque it could experience?