Question 1

Which of the following best explains why breaking a bar magnet in half does NOT result in isolated north and south poles?

Accepted Answer

Each half becomes a smaller magnet with both a north and south pole due to the alignment of magnetic domains.

Question 2

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

Accepted Answer

Perpendicular to both $$\vec{v}$$ and $$\vec{B}$$, following the right-hand rule.

Question 3

Which of the following statements about Earth's magnetic field is TRUE?

Accepted Answer

It is generated by electric currents in the liquid iron outer core.

Question 4

Why does a magnetic field do NO work on a moving charged particle?

Accepted Answer

The magnetic force is always perpendicular to the particle's velocity.

Question 5

Which of the following actions will NOT increase the strength of an electromagnet made from a coil of wire?

Accepted Answer

Decreasing the current through the coil.

Question 6

A wire carrying current $$I is $$placed in a uniform magnetic field $$\vec{B}$$ such that the current is perpendicular to the field. What is the magnitude of the force on a length $$L of $$the wire?

Accepted Answer

$$F = I B L$$

Question 7

Which of the following best describes the role of magnetic domains in the magnetization of iron?

Accepted Answer

Domains align with an external magnetic field, increasing the net magnetization.

Question 8

A solenoid is constructed with $$N$$ turns of wire, carrying current $$I. $$Which change will result in the GREATEST increase in the magnetic field inside the solenoid?

Accepted Answer

Inserting an iron core and increasing both $$N$$ and $$I.$$

Question 9

Which of the following is a real-world application that relies on the principle of magnetic force on a current-carrying wire?

Accepted Answer

Electric motors converting electrical energy into mechanical energy.

Question 10

A beam of electrons enters a region with a uniform magnetic field directed into the page. What is the path of the electrons?

Accepted Answer

They follow a circular path perpendicular to the field.

Question 11

Which of the following is NOT a similarity between electric and magnetic fields?

Accepted Answer

Magnetic monopoles exist, but electric monopoles do not.

Question 12

Which of the following best explains why Earth's magnetic field is important for life on Earth?

Accepted Answer

It deflects harmful charged particles from the solar wind and cosmic rays.

Question 13

Which of the following is the dominant contributor to the magnetic field of most materials?

Accepted Answer

The intrinsic spin of electrons.

Question 14

A maglev train floats above its track due to which physical principle?

Accepted Answer

Repulsive magnetic forces between superconducting magnets and coils in the track.

Question 15

Which of the following statements about the force between two magnets is correct?

Accepted Answer

The force each magnet exerts on the other is equal in magnitude and opposite in direction.

Question 16

Which of the following is a correct statement about the operation of a galvanometer?

Accepted Answer

A current-carrying coil in a magnetic field experiences a torque, causing a pointer to deflect.

Question 17

Which of the following is NOT a way to destroy the magnetization of a permanent magnet?

Accepted Answer

Cooling the magnet to very low temperatures.

Question 18

Which of the following best describes the difference between an electric motor and a generator?

Accepted Answer

A motor converts electrical energy to mechanical energy, while a generator does the reverse.

Question 19

Which of the following organisms is known to use Earth's magnetic field for navigation due to the presence of magnetite crystals?

Accepted Answer

Pigeons.

Question 20

A straight wire carries a current upward. What is the direction of the magnetic field directly to the east of the wire?

Accepted Answer

South.

Chapter 24: Magnetism – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard