Question 1

Which of the following statements best describes the behavior of magnetic poles when a bar magnet is broken in half?

Accepted Answer

Each half becomes a new magnet with both a north and a south pole.

Question 2

A proton moves with velocity $$\vec{v}$$ perpendicular to a uniform magnetic field $$\vec{B}. $$What is the magnitude of the force acting on the proton?

Accepted Answer

$$F = qvB$$

Question 3

Which of the following is true about the direction of the magnetic force on a moving charge in a magnetic field?

Accepted Answer

It is perpendicular to both the velocity of the charge and the magnetic field.

Question 4

A beam of electrons is moving straight toward you. If you place the north pole of a magnet directly above the beam so that the magnetic field points straight down, in which direction will the electron beam deflect?

Accepted Answer

To the right

Question 5

The magnetic flux $$\phi_B$$ through a surface of area $$A in a $$uniform magnetic field $$B at an $$angle $$	heta to $$the normal of the surface is given by:

Accepted Answer

$$\phi_B = BA \cos 	heta$$

Question 6

A charged particle moves in a circle of radius $$R in a $$uniform magnetic field $$B. $$Which equation gives the radius of the path?

Accepted Answer

$$R = \frac{mv}{|q|B}$$

Question 7

In a velocity selector, charged particles pass through undeflected if their speed $$v$$ satisfies which condition?

Accepted Answer

$$v = \frac{E}{B}$$

Question 8

A rectangular coil with $$N$$ turns, area $$A$$, and current $$I is $$placed in a uniform magnetic field $$B. $$What is the magnitude of its magnetic dipole moment?

Accepted Answer

$$\mu = NIA$$

Question 9

A current-carrying wire of length $$l is $$placed in a uniform magnetic field $$B at an $$angle $$\phi. $$What is the magnitude of the force on the wire?

Accepted Answer

$$F = IlB \sin \phi$$

Question 10

Which of the following best describes the Earth's magnetic field?

Accepted Answer

The geomagnetic north pole is actually a magnetic south pole.

Question 11

A mass spectrometer separates ions based on their:

Accepted Answer

Mass-to-charge ratio

Question 12

The torque $$	au on a $$current loop of area $$A$$ carrying current $$I in a $$uniform magnetic field $$B is $$given by:

Accepted Answer

$$	au = IAB \sin 	heta$$

Question 13

Which of the following is NOT a property of magnetic field lines?

Accepted Answer

They are lines of magnetic force.

Question 14

A charged particle moves through a region with both electric field $$\vec{E}$$ and magnetic field $$\vec{B}$$ present. For the particle to move at constant velocity, the fields must be:

Accepted Answer

Perpendicular to each other

Question 15

The Hall effect is used to measure which property of a material?

Accepted Answer

Charge carrier density

Question 16

A circular loop of wire carries a constant current and is placed in a uniform magnetic field. The net force on the loop is:

Accepted Answer

Zero

Question 17

Which of the following best explains why MRI machines use strong magnetic fields?

Accepted Answer

To align the magnetic moments of nuclei in the body for imaging

Question 18

A proton and an electron move with the same speed perpendicular to the same uniform magnetic field. How do the magnitudes of the forces and accelerations they experience compare?

Accepted Answer

The forces are equal in magnitude, but the accelerations are different.

Question 19

A current-carrying wire is placed in a uniform magnetic field. If the current is reversed, what happens to the direction of the force on the wire?

Accepted Answer

The force reverses direction.

Magnetic Field and Magnetic Forces: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards