Question 1

Which of the following statements best explains why, when a bar magnet is cut in half, each piece still has both a north and a south pole?

Accepted Answer

The magnetic domains in each half realign to form new poles.

Question 2

A charged particle moves perpendicular to a uniform magnetic field. Which of the following best describes its path and the force acting on it?

Accepted Answer

The particle moves in a circle, with the force always perpendicular to its velocity.

Question 3

Which equation gives the magnitude of the force on a length $$l of $$wire carrying current $$I in a $$magnetic field $$B at an $$angle $$	heta$$?

Accepted Answer

$$F = I l B \sin 	heta$$

Question 4

A long straight wire carries a current $$I. $$What is the expression for the magnetic field $$B at a $$distance $$r$$ from the wire?

Accepted Answer

$$B = \frac{\mu_0$ I}{2 \pi r}$$

Question 5

Two long, parallel wires carry currents $$I_1$$ and $$I_2 in $$the same direction. What is the nature of the force between them?

Accepted Answer

They attract each other.

Question 6

Which of the following best describes the magnetic field inside a long, tightly wound solenoid carrying current $$I$$?

Accepted Answer

The field is nearly uniform and parallel to the axis of the solenoid.

Question 7

Ampère’s Law relates the magnetic field around a closed loop to which of the following?

Accepted Answer

The total current passing through the loop.

Question 8

A mass spectrometer separates ions based on their mass-to-charge ratio. If the electric field $$E$$ and magnetic field $$B$$ are perpendicular, what speed $$v$$ allows a particle to pass through undeflected?

Accepted Answer

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

Question 9

Which of the following is a correct statement about ferromagnetic domains?

Accepted Answer

Domains are regions where the magnetic moments are aligned in the same direction.

Question 10

A current loop of area $$A$$ and $$N$$ turns carries current $$I in a $$uniform magnetic field $$B. $$What is the expression for the maximum torque $$	au on $$the loop?

Accepted Answer

$$	au = N I A B$$

Question 11

Which of the following devices uses the torque on a current loop to measure electric current?

Accepted Answer

Galvanometer

Question 12

A loudspeaker converts electrical signals into sound using which physical principle?

Accepted Answer

A magnet exerts a force on a current-carrying wire, causing mechanical vibrations.

Question 13

Which of the following best describes the hysteresis curve for a ferromagnetic material?

Accepted Answer

It shows the lag between the magnetization and the applied magnetic field.

Question 14

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

Accepted Answer

$$F = q v B$$

Question 15

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 always perpendicular to both the velocity of the charge and the magnetic field.

Question 16

The SI unit of magnetic field strength is the tesla (T). Which of the following is equivalent to one tesla?

Accepted Answer

$$1\ \mathrm{T} = 1\ \mathrm{N}/(\mathrm{A} \cdot \mathrm{m})$$

Question 17

Which of the following best explains why the Earth's geographic North Pole is actually a magnetic south pole?

Accepted Answer

The north end of a compass needle (a north pole) is attracted to the Earth's magnetic south pole, which is near the geographic North Pole.

Question 18

A solenoid has $$N$$ turns, length $$\ell$$, and carries current $$I. $$What is the expression for the magnetic field $$B$$ inside the solenoid?

Accepted Answer

$$B = \frac{\mu_0$ N I}{\ell}$$

Question 19

Which of the following is a practical application of the force between two parallel wires?

Accepted Answer

Defining the ampere, the SI unit of current.

Chapter 20: Magnetism – Structured Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards