Q: Which equation gives the force on a length $$L of $$wire carrying current $$I in a $$uniform magnetic field $$\vec{B}$$?

$$\vec{F} = I \vec{L} \times \vec{B}$$

Question 1

Which of the following best describes why the Earth acts as a giant magnet?

Accepted Answer

Because of electric currents in its molten iron core.

Question 2

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

Accepted Answer

Two magnets, each with a north and a south pole.

Question 3

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

Accepted Answer

Iron nail

Question 4

A charged particle with charge $$q$$ and velocity $$\vec{v}$$ enters a uniform magnetic field $$\vec{B}$$ perpendicular to its velocity. What is the magnitude of the force on the particle?

Accepted Answer

$$F = |q|vB$$

Question 5

Which of the following statements about magnetic poles is correct?

Accepted Answer

Like poles repel and unlike poles attract.

Question 6

A current-carrying wire produces a magnetic field. Which rule helps you determine the direction of this field?

Accepted Answer

Right-hand rule

Question 7

A positively charged particle moves perpendicular to a uniform magnetic field. What is the resulting path of the particle?

Accepted Answer

A circle

Question 8

Which of the following is NOT a practical application of magnetism?

Accepted Answer

Solar panels

Question 9

A long, straight wire carries a current $$I$$ out of the page. What is the direction of the magnetic field at a point to the right of the wire?

Accepted Answer

Downward

Question 10

Two parallel wires carry currents in the same direction. What is the force between them?

Accepted Answer

They attract each other.

Question 11

A bar magnet is held above a positively charged plastic rod. What happens?

Accepted Answer

The rod is unaffected by the magnet.

Question 12

Which of the following best explains why most materials are not attracted to magnets?

Accepted Answer

Their electrons are paired and their magnetic moments cancel.

Question 13

A current loop in a magnetic field experiences which of the following?

Accepted Answer

A torque

Question 14

Which of the following is true about the magnetic field lines around a current-carrying wire?

Accepted Answer

They form concentric circles around the wire.

Question 15

A compass needle aligns with the Earth's magnetic field because:

Accepted Answer

A torque acts on the needle, aligning it with the field.

Question 16

Which equation gives the force on a length $$L of $$wire carrying current $$I in a $$uniform magnetic field $$\vec{B}$$?

Accepted Answer

$$\vec{F} = I \vec{L} 	imes \vec{B}$$

Question 17

A proton moves with velocity $$\vec{v}$$ perpendicular to a magnetic field $$\vec{B}. $$What is the radius $$r of $$its circular path?

Accepted Answer

$$r = \frac{mv}{qB}$$

Question 18

Which of the following is a correct statement about magnetic field lines?

Accepted Answer

They are closer together where the magnetic field is stronger.

Question 19

Which of the following is a reason why magnetism is important in modern technology?

Accepted Answer

It is essential for data storage in hard drives.

Question 20

A solenoid is best described as:

Accepted Answer

A coil of wire that produces a nearly uniform magnetic field inside.

Chapter 29: Magnetic Fields – Physics with Calculus Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards