Question 1

At one instant an electron (charge = -1.6 *10-19C)  is moving in the xy plane, the components of its velocity being vx = 5 *105 m/s and vy = 3 *105 m/s. A magnetic field of 0.8 T is in the positive x direction. At that instant the magnitude of the magnetic force on the electron is:

Accepted Answer

A)   0
B)   3.8 *10-14 N
C)   5.1 * 10-14 N
D)   6.4 * 10-14 N
E)   7.5*10-14 N

Question 2

The diagrms show five possible orientations of a magnetic dipole  in a uniform magnetic field  For which of these is the potential energy the greatest?

Accepted Answer

A)   I
B)   II
C)   III
D)   IV
E)   V

Question 3

A uniform magnetic field is in the positive z direction. A positively charged particle is moving in the positive x direction through the field. The net force on the particle can be made zero by applying an electric field in what direction?

Accepted Answer

A)   Positive y
B)   Negative y
C)   Positive x
D)   Negative x
E)   Positive z

Question 4

At one instant an electron (charge = -1.6 *10-19C)  is moving in the xy plane, the components of its velocity being vx = 5 * 105 m/s and vy = 3 * 105 m/s. A magnetic field of 0.8 T is in the positive x direction. At that instant the magnitude of the magnetic force on the electron is:

Accepted Answer

A)   0
B)   2.6 * 10-14 N
C)   3.8 * 10-14 N
D)   6.4 * 10-14 N
E)   1.0 * 10-14 N

Question 5

A magnetic field CANNOT:

Accepted Answer

A)   exert a force on a charge
B)   accelerate a charge
C)   change the momentum of a charge
D)   change the kinetic energy of a charge
E)   exist

Question 6

An electron travels due north through a vacuum in a region of uniform magnetic field  that is also directed due north. It will:

Accepted Answer

A)   be unaffected by the field
B)   speed up
C)   slow down
D)   follow a right-handed corkscrew path
E)   follow a left-handed corkscrew path

Question 7

An electron and a proton both each travel with equal speeds around circular orbits in the same uniform magnetic field, as shown in the diagram (not to scale) . The field is into the page on the diagram. Because the electron is less massive than the proton and because the electron is negatively charged and the proton is positively charged:

Accepted Answer

A)   the electron travels clockwise around the smaller circle and the proton travels counterclockwise around the larger circle.
B)   the electron travels counterclockwise around the smaller circle and the proton travels clockwise around the larger circle
C)   the electron travels clockwise around the larger circle and the proton travels counterclockwise around the smaller circle
D)   the electron travels counterclockwise around the larger circle and the proton travels clockwise around the smaller circle
E)   the electron travels counterclockwise around the smaller circle and the proton travels counterclockwise around the larger circle

Question 8

An electron is launched with velocity o. As a result, the electron follows a helix, its velocity vector   returning to its initial value in a time interval of: A)  2πm/eB B)  2πmv/eB C)  2πmv sin 	heta /eB D)  2πmv cos 	heta /eB E)  none of these " class="answers-bank-image d-inline" rel="preload" > in a uniform magnetic field o. As a result, the electron follows a helix, its velocity vector   returning to its initial value in a time interval of: A)  2πm/eB B)  2πmv/eB C)  2πmv sin 	heta /eB D)  2πmv cos 	heta /eB E)  none of these " class="answers-bank-image d-inline" rel="preload" > The angle  θ	hetaθ  between o. As a result, the electron follows a helix, its velocity vector   returning to its initial value in a time interval of: A)  2πm/eB B)  2πmv/eB C)  2πmv sin 	heta /eB D)  2πmv cos 	heta /eB E)  none of these " class="answers-bank-image d-inline" rel="preload" > is between 0 and 90o. As a result, the electron follows a helix, its velocity vector o. As a result, the electron follows a helix, its velocity vector   returning to its initial value in a time interval of: A)  2πm/eB B)  2πmv/eB C)  2πmv sin 	heta /eB D)  2πmv cos 	heta /eB E)  none of these " class="answers-bank-image d-inline" rel="preload" > returning to its initial value in a time interval of:

Accepted Answer

A)   2πm/eB
B)   2πmv/eB
C)   2πmv sin θ	hetaθ /eB
D)   2πmv cos θ	hetaθ /eB
E)   none of these

Exam 28: Magnetic Fields

The diagrms show five possible orientations of a magnetic dipole in a uniform magnetic field For which of these is the potential energy the greatest?

Correct Answer
verified

At one instant an electron (charge = -1.6 10^-¹⁹C) is moving in the xy plane, the components of its velocity being v_x = 5 10⁵ m/s and v_y = 3 * 10⁵ m/s. A magnetic field of 0.8 T is in the positive x direction. At that instant the magnitude of the magnetic force on the electron is:

Correct Answer
verified

A magnetic field CANNOT:

Correct Answer
verified

At one instant an electron (charge = -1.6 10^-¹⁹C) is moving in the xy plane, the components of its velocity being v_x = 5 10⁵ m/s and v_y = 3 *10⁵ m/s. A magnetic field of 0.8 T is in the positive x direction. At that instant the magnitude of the magnetic force on the electron is:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

An electron travels due north through a vacuum in a region of uniform magnetic field that is also directed due north. It will:

Correct Answer
verified

A uniform magnetic field is in the positive z direction. A positively charged particle is moving in the positive x direction through the field. The net force on the particle can be made zero by applying an electric field in what direction?

Correct Answer
verified

Exam 28: Magnetic Fields

The diagrms show five possible orientations of a magnetic dipole in a uniform magnetic field For which of these is the potential energy the greatest?

Correct AnswerverifiedShow Answer

At one instant an electron (charge = -1.6 *10-19C) is moving in the xy plane, the components of its velocity being vx = 5 * 105 m/s and vy = 3 * 105 m/s. A magnetic field of 0.8 T is in the positive x direction. At that instant the magnitude of the magnetic force on the electron is:

Correct AnswerverifiedShow Answer

A magnetic field CANNOT:

Correct AnswerverifiedShow Answer

At one instant an electron (charge = -1.6 *10-19C) is moving in the xy plane, the components of its velocity being vx = 5 *105 m/s and vy = 3 *105 m/s. A magnetic field of 0.8 T is in the positive x direction. At that instant the magnitude of the magnetic force on the electron is:

Correct AnswerverifiedShow Answer

An electron is launched with velocity in a uniform magnetic field The angle θ\thetaθ between is between 0 and 90o. As a result, the electron follows a helix, its velocity vector returning to its initial value in a time interval of:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

An electron travels due north through a vacuum in a region of uniform magnetic field that is also directed due north. It will:

Correct AnswerverifiedShow Answer

A uniform magnetic field is in the positive z direction. A positively charged particle is moving in the positive x direction through the field. The net force on the particle can be made zero by applying an electric field in what direction?

Correct AnswerverifiedShow Answer

Correct Answer
verified

At one instant an electron (charge = -1.6 10^-¹⁹C) is moving in the xy plane, the components of its velocity being v_x = 5 10⁵ m/s and v_y = 3 * 10⁵ m/s. A magnetic field of 0.8 T is in the positive x direction. At that instant the magnitude of the magnetic force on the electron is:

Correct Answer
verified

Correct Answer
verified

At one instant an electron (charge = -1.6 10^-¹⁹C) is moving in the xy plane, the components of its velocity being v_x = 5 10⁵ m/s and v_y = 3 *10⁵ m/s. A magnetic field of 0.8 T is in the positive x direction. At that instant the magnitude of the magnetic force on the electron is:

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified