Q: The force on a charged particle moving with velocity $$\vec{v} in a $$magnetic field $$\vec{B} is $$given by which equation?

$$\vec{F} = q\vec{v} \times \vec{B}$$

Question 1

Which of the following statements best describes what happens when a bar magnet is cut in half?

Accepted Answer

Each half becomes a weaker magnet, but both have a north and a south pole.

Question 2

A compass needle aligns itself with the Earth's magnetic field. What does this indicate about the nature of the compass needle?

Accepted Answer

It is a small magnet with a north and south pole.

Question 3

Which material is most likely to be attracted to a bar magnet?

Accepted Answer

Iron

Question 4

If the north pole of one bar magnet is brought near the north pole of another bar magnet, what will happen?

Accepted Answer

They will repel each other.

Question 5

Which of the following best describes the direction of magnetic field lines around a bar magnet?

Accepted Answer

They form closed loops, exiting the north pole and entering the south pole.

Question 6

A current-carrying wire produces a magnetic field. What is the shape of the magnetic field lines around a long, straight wire?

Accepted Answer

Circles centered on the wire

Question 7

Which rule helps you determine the direction of the magnetic field around a current-carrying wire?

Accepted Answer

Right-hand rule

Question 8

The strength of the magnetic field $$B at a $$distance $$r$$ from a long, straight wire carrying current $$I is $$given by which equation?

Accepted Answer

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

Question 9

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

Accepted Answer

It moves in a circular path.

Question 10

The force on a charged particle moving with velocity $$\vec{v} in a $$magnetic field $$\vec{B} is $$given by which equation?

Accepted Answer

$$\vec{F} = q\vec{v} 	imes \vec{B}$$

Question 11

A solenoid is constructed with $$N$$ turns, length $$L$$, and carries current $$I. $$The magnetic field inside the solenoid is given by:

Accepted Answer

$$B = \mu_0$ n I$$, where $$n = \frac{N}{L}$$

Question 12

Which of the following is true about the magnetic field inside a long solenoid?

Accepted Answer

It is strong and nearly uniform.

Question 13

A wire carrying current $$I is $$placed perpendicular to a uniform magnetic field $$B. $$The length of the wire in the field is $$L. $$What is the magnitude of the force on the wire?

Accepted Answer

$$F = I L B$$

Question 14

If two parallel wires carry currents in the same direction, what is the nature of the force between them?

Accepted Answer

They attract each other.

Question 15

A proton moves to the right in a region where the magnetic field points into the page. What is the direction of the magnetic force on the proton?

Accepted Answer

Upward

Question 16

Which of the following best explains why the leaves of an electroscope are not affected by a nearby magnet?

Accepted Answer

Magnetism only affects moving charges, not stationary ones.

Question 17

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 18

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

Accepted Answer

They form complete closed curves.

Question 19

A charged particle moves parallel to a uniform magnetic field. What is the force on the particle?

Accepted Answer

Zero

Question 20

The radius $$r of $$the circular path of a charged particle of mass $$m$$ and charge $$q$$ moving at speed $$v$$ perpendicular to a magnetic field $$B is$$:

Accepted Answer

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

Magnetic Fields and Forces: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards