Question 1

Which of the following statements best describes the difference between electric charges and magnetic poles?

Accepted Answer

Electric charges can exist independently, while magnetic poles always come in pairs (dipoles).

Question 2

A bar magnet is cut in half. What is the result?

Accepted Answer

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

Question 3

Which of the following materials is most likely to be attracted to a magnet?

Accepted Answer

Iron

Question 4

What is the direction of the magnetic field at a point near a bar magnet?

Accepted Answer

The direction a north pole of a compass would point at that location.

Question 5

Which of the following best explains why a compass needle points north?

Accepted Answer

Earth itself acts as a giant magnet, with its geographic north pole being a magnetic south pole.

Question 6

A current-carrying wire produces a magnetic field. What is the direction of the magnetic field around the wire?

Accepted Answer

The field forms concentric circles around the wire, with direction given by the right-hand rule.

Question 7

Which of the following is the correct right-hand rule for the direction of the magnetic field around a current-carrying wire?

Accepted Answer

Point your right thumb in the direction of the current; your fingers curl in the direction of the magnetic field.

Question 8

If a charged particle moves parallel to a uniform magnetic field, what is the force acting on it?

Accepted Answer

$$\vec{F} = 0$$

Question 9

Which equation gives the magnitude of the magnetic field at a distance $$r$$ from a long, straight wire carrying current $$I$$?

Accepted Answer

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

Question 10

A charged particle moves with velocity $$\vec{v}$$ perpendicular to a uniform magnetic field $$\vec{B}. $$What is the resulting motion?

Accepted Answer

The particle moves in a circle with radius $$r = \frac{mv}{qB}.$$

Question 11

Which of the following best describes the force between two parallel wires carrying currents $$I_1$$ and $$I_2 in $$the same direction?

Accepted Answer

The wires attract each other.

Question 12

What is the SI unit of magnetic field strength?

Accepted Answer

Tesla (T)

Question 13

Which of the following is true about the cross product $$\vec{A} 	imes \vec{B}$$?

Accepted Answer

It is perpendicular to the plane formed by $$\vec{A}$$ and $$\vec{B}.$$

Question 14

A solenoid is used to create a uniform magnetic field. Which equation gives the field inside an ideal solenoid?

Accepted Answer

$$B = \mu_0$ n I$$

Question 15

Which of the following best explains why most materials are not magnetic?

Accepted Answer

The magnetic moments of electrons in most materials cancel each other out.

Question 16

What is the magnetic dipole moment $$m of a $$current-carrying loop of area $$A$$ and current $$I$$?

Accepted Answer

$$m = A I$$

Question 17

Which of the following is a property of ferromagnetic materials?

Accepted Answer

Their atomic magnetic moments tend to align in the same direction.

Question 18

A wire carries a current $$I in $$the $$+x$$ direction and is placed in a uniform magnetic field $$\vec{B} in $$the $$+y$$ direction. What is the direction of the force on the wire?

Accepted Answer

In the $$+z$$ direction

Question 19

Which of the following best describes the effect of an external magnetic field on a ferromagnetic material?

Accepted Answer

It can induce a net magnetic dipole by aligning magnetic domains.

Question 20

Which of the following is NOT a correct statement about the magnetic field lines around a bar magnet?

Accepted Answer

They begin at the north pole and end at the south pole.

Magnetism and Magnetic Fields: Foundations and Applications

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