Question 1

Doubling the current,number of turns,the area,and the ambient magnetic field for a coil changes the maximum torque it experiences by what factor?

Accepted Answer

A)  2 
B)  4 
C)  8 
D)  16 
E)  32 
A)  2 
B)  4 
C)  8 
D)  16 
E)  32

Question 2

A solenoid of radius 1.1 cm produces a magnetic field at its center is 0.28 T.What is the magnetic flux through the center of the solenoid?

Accepted Answer

A)  1.1 $\times$ 10-4 T·m2 
B)  2.2 $\times$ 10-4 T·m2 
C)  3.3 $\times$ 10-3 T·m2 
D)  2.2 $\times$ 10-3 T·m2 
E)  3.3 $\times$ 10-4 T·m2 
A)  1.1 $\times$ 10-4 T·m2 
B)  2.2 $\times$ 10-4 T·m2 
C)  3.3 $\times$ 10-3 T·m2 
D)  2.2 $\times$ 10-3 T·m2 
E)  3.3 $\times$ 10-4 T·m2

Question 3

All materials are magnetic and are described by one of these three properties.Select the property that is invalid.

Accepted Answer

A)  ferromagnetic 
B)  nonmagnetic 
C)  diamagnetic 
D)  paramagnetic 
A)  ferromagnetic 
B)  nonmagnetic 
C)  diamagnetic 
D)  paramagnetic

Question 4

The temperature at which ferromagnetic materials transform into paramagnetic materials is called the

Accepted Answer

A)  Celsius temperature. 
B)  Carnot temperature. 
C)  crossover temperature. 
D)  Curie temperature. 
E)  chaos temperature. 
A)  Celsius temperature. 
B)  Carnot temperature. 
C)  crossover temperature. 
D)  Curie temperature. 
E)  chaos temperature.

Question 5

The SI unit of magnetic field is the tesla,which is equivalent to a

Accepted Answer

A)  N/C. 
B)  A/m. 
C)  N/(A·m). 
D)  magnon. 
E)  None of these choices are correct. 
A)  N/C. 
B)  A/m. 
C)  N/(A·m). 
D)  magnon. 
E)  None of these choices are correct.

Question 6

Find the circulation for the path shown.

Accepted Answer

A)  -(4 
A) $\mu$0 
B)  (4 
A) $\mu$0 
C)  -(28 
A) $\mu$0 
D)  (28 
A) $\mu$0 
E)  -(7 
A) $\mu$0 
A)  -(4 
A) $\mu$0 
B)  (4 
A) $\mu$0 
C)  -(28 
A) $\mu$0 
D)  (28 
A) $\mu$0 
E)  -(7 
A) $\mu$0

Question 7

A power line carries 1000 A at a height of 20 m above the ground.What is the resulting magnetic field at ground level?

Accepted Answer

A)  50 mT 
B)  0.13 mT 
C)  13 $\mu$T 
D)  10 $\mu$T 
E)  5.0 $\mu$T 
A)  50 mT 
B)  0.13 mT 
C)  13 $\mu$T 
D)  10 $\mu$T 
E)  5.0 $\mu$T

Question 8

Doubling the magnetic field in a proton synchrotron changes the maximum kinetic energy of the protons by what amount?

Accepted Answer

A)  It is quadrupled. 
B)  It is doubled. 
C)  It remains the same. 
D)  it is halved 
E)  It is quartered. 
A)  It is quadrupled. 
B)  It is doubled. 
C)  It remains the same. 
D)  it is halved 
E)  It is quartered.

Question 9

A bar magnet has a north pole and a south pole.This arrangement is referred to as a

Accepted Answer

A)  monopole. 
B)  dipole. 
C)  bipole. 
D)  equipole. 
E)  oppopole. 
A)  monopole. 
B)  dipole. 
C)  bipole. 
D)  equipole. 
E)  oppopole.

Question 10

The magnetism of the Earth acts approximately as if it originates from a huge bar magnet within the Earth.Which of the following statements are true?

Accepted Answer

A)  the north magnetic pole of the Earth is located at the Earth's North Pole 
B)  the south magnetic pole of the Earth is located at the Earth's South Pole 
C)  the Earth's magnetic field is vertical at the equator 
D)  the Earths north magnetic pole is magnetically a south pole 
E)  None of these statements are true. 
A)  the north magnetic pole of the Earth is located at the Earth's North Pole 
B)  the south magnetic pole of the Earth is located at the Earth's South Pole 
C)  the Earth's magnetic field is vertical at the equator 
D)  the Earths north magnetic pole is magnetically a south pole 
E)  None of these statements are true.

Question 11

A negative ion is moving east near the equator where the Earth's magnetic field is horizontal to the north.The direction of the magnetic force on the ion is

Accepted Answer

A)  north. 
B)  south. 
C)  up. 
D)  down. 
E)  not meaningful since the force is zero. 
A)  north. 
B)  south. 
C)  up. 
D)  down. 
E)  not meaningful since the force is zero.

Question 12

A flat conductor of thickness 0.500 mm is placed in a magnetic field of 0.200 T perpendicular to the flat surface.If there are 8.00 $\times$ 1024 charge carriers (i.e.,electrons) per m3,what is the Hall voltage generated when 3.40 A flows along the conductor?

Accepted Answer

A)  0.266 mV 
B)  0.531 mV 
C)  0.797 mV 
D)  1.06 mV 
E)  2.12 mV 
A)  0.266 mV 
B)  0.531 mV 
C)  0.797 mV 
D)  1.06 mV 
E)  2.12 mV

Question 13

A wire bearing current of 1.25 A crosses a region in which there is a uniform B field in the +y direction.The wire is inclined at an angle of 75 degrees above the +x direction.What is the magnitude of the force on the wire,if the magnetic field region spans 15 cm in the x direction?

Accepted Answer

A)  0.19 N 
B)  0.70 N 
C)  0.18 N 
D)  0.05 N 
A)  0.19 N 
B)  0.70 N 
C)  0.18 N 
D)  0.05 N

Question 14

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 15

A charged particle enters a region of magnetic field at a speed of 2.8 $\times$ 104 m/s, at an angle of 37 degrees relative to the magnetic field direction.What will be the magnitude of the component of the particle's velocity that is parallel to the magnetic field while it is in this region?

Accepted Answer

A)  Insufficient information is given. 
B)  2.2 $\times$ 104 m/s 
C)  2.1 $\times$ 104 m/s 
D)  1.7 $\times$ 104 m/s 
E)  2.8 $\times$ 104 m/s 
A)  Insufficient information is given. 
B)  2.2 $\times$ 104 m/s 
C)  2.1 $\times$ 104 m/s 
D)  1.7 $\times$ 104 m/s 
E)  2.8 $\times$ 104 m/s

Question 16

A straight wire is carrying a current upward.Observed from above (i.e.,looking downward towards the wire),the magnetic field lines are

Accepted Answer

A)  radially outward. 
B)  radially inward. 
C)  forming clockwise circles. 
D)  forming counter-clockwise circles. 
E)  directed toward the observer. 
A)  radially outward. 
B)  radially inward. 
C)  forming clockwise circles. 
D)  forming counter-clockwise circles. 
E)  directed toward the observer.

Question 17

A proton is moving at 2.0 $\times$ 107 m/s in a magnetic field of 30 mT.What is the magnetic force on the proton?

Accepted Answer

A)  9.6 $\times$ 10-14 N 
B)  4.8 $\times$ 10-14 N 
C)  0.0 
D)  6.0 $\times$ 10-5 N 
E)  More information is needed. 
A)  9.6 $\times$ 10-14 N 
B)  4.8 $\times$ 10-14 N 
C)  0.0 
D)  6.0 $\times$ 10-5 N 
E)  More information is needed.

Question 18

Cathode rays are

Accepted Answer

A)  x-rays. 
B)  $\gamma$-rays. 
C)  electrons. 
D)  protons. 
E)  neutrons. 
A)  x-rays. 
B)  $\gamma$-rays. 
C)  electrons. 
D)  protons. 
E)  neutrons.

Question 19

Two concentric circular wire loops in the same plane each carry a current.The larger loop as a current of 8.46 A circulating clockwise and has a radius of 6.20 cm.The smaller loop has a radius of 4.42 cm.What is the magnitude and direction of the current in the smaller loop if the total magnetic field at the center of the system is zero?

Accepted Answer

A)  6.03 A CCW 
B)  6.03 A CW 
C)  12.8 A CCW 
D)  12.8 A CW 
A)  6.03 A CCW 
B)  6.03 A CW 
C)  12.8 A CCW 
D)  12.8 A CW

Question 20

A long straight wire is carrying a current of 2.4 A in a region where the magnetic field is perpendicular to the wire.If the magnetic field is 0.52 mT,what is the magnitude of the force on 3.0 m of the wire?

Accepted Answer

A)  1.2 $\times$ 10-3 N 
B)  3.7 $\times$ 10-3 N 
C)  7.2 $\times$ 10-3 N 
D)  3.7 N 
E)  7.2 N 
A)  1.2 $\times$ 10-3 N 
B)  3.7 $\times$ 10-3 N 
C)  7.2 $\times$ 10-3 N 
D)  3.7 N 
E)  7.2 N

Exam 19: Magnetic Forces and Fields

Doubling the current,number of turns,the area,and the ambient magnetic field for a coil changes the maximum torque it experiences by what factor?

A solenoid of radius 1.1 cm produces a magnetic field at its center is 0.28 T.What is the magnetic flux through the center of the solenoid?

All materials are magnetic and are described by one of these three properties.Select the property that is invalid.

The temperature at which ferromagnetic materials transform into paramagnetic materials is called the

The SI unit of magnetic field is the tesla,which is equivalent to a

Find the circulation for the path shown.

A power line carries 1000 A at a height of 20 m above the ground.What is the resulting magnetic field at ground level?

Doubling the magnetic field in a proton synchrotron changes the maximum kinetic energy of the protons by what amount?

A bar magnet has a north pole and a south pole.This arrangement is referred to as a

The magnetism of the Earth acts approximately as if it originates from a huge bar magnet within the Earth.Which of the following statements are true?

A negative ion is moving east near the equator where the Earth's magnetic field is horizontal to the north.The direction of the magnetic force on the ion is

A flat conductor of thickness 0.500 mm is placed in a magnetic field of 0.200 T perpendicular to the flat surface.If there are 8.00 ×\times× 1024 charge carriers (i.e.,electrons) per m3,what is the Hall voltage generated when 3.40 A flows along the conductor?

A wire bearing current of 1.25 A crosses a region in which there is a uniform B field in the +y direction.The wire is inclined at an angle of 75 degrees above the +x direction.What is the magnitude of the force on the wire,if the magnetic field region spans 15 cm in the x direction?

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 charged particle enters a region of magnetic field at a speed of 2.8 ×\times× 104 m/s, at an angle of 37 degrees relative to the magnetic field direction.What will be the magnitude of the component of the particle's velocity that is parallel to the magnetic field while it is in this region?

A straight wire is carrying a current upward.Observed from above (i.e.,looking downward towards the wire),the magnetic field lines are

A proton is moving at 2.0 ×\times× 107 m/s in a magnetic field of 30 mT.What is the magnetic force on the proton?

Cathode rays are

A long straight wire is carrying a current of 2.4 A in a region where the magnetic field is perpendicular to the wire.If the magnetic field is 0.52 mT,what is the magnitude of the force on 3.0 m of the wire?

Introduction

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A flat conductor of thickness 0.500 mm is placed in a magnetic field of 0.200 T perpendicular to the flat surface.If there are 8.00 $\times$ 10²⁴ charge carriers (i.e.,electrons) per m³,what is the Hall voltage generated when 3.40 A flows along the conductor?

A charged particle enters a region of magnetic field at a speed of 2.8 $\times$ 10⁴ m/s, at an angle of 37 degrees relative to the magnetic field direction.What will be the magnitude of the component of the particle's velocity that is parallel to the magnetic field while it is in this region?

A proton is moving at 2.0 $\times$ 10⁷ m/s in a magnetic field of 30 mT.What is the magnetic force on the proton?