Chapter 22

Question 1

Magnets

Answer 1

Like poles repel, unlike poles attract

Question 2

Iron

Answer 2

If an unmagnetized piece of iron is rubbed with a magnet or placed near a strong permanent magnet, the piece of iron eventually becomes MAGNETIZED

Question 3

Magnetite

Answer 3

Naturally occurring magnetic because they have been subjected to Earth’s magnetic field for a long time

Question 4

Magnetic domains

Answer 4

1. random and unmagnetized

Question 5

Magnetic domains

Answer 5

2. external B is applied, domains align with B

Question 6

Magnetic domains

Answer 6

3. B strengthens, domains aligned grow larger

Question 7

Ferromagnetic

Answer 7

(aligned domain, strong) having a high susceptibility to magnetization, the strength of which depends on that of the applied magnetizing field, and which may persist after removal of the applied field.

Question 8

Paramagnetic

Answer 8

(aligned domain, weak, aluminum) having a low susceptibility to magnetization, the strength of which depends on that of the applied magnetizing field, and which may persist after removal of the applied field.

Question 9

Diamagnetic

Answer 9

(OPPOSITE domain, weak, water molecules) having a weak susceptibility to magnetization, the strength of which depends on that of the applied magnetizing field, and which may persist after removal of the applied field.

Question 10

Magnetic field lines

Answer 10

N to S

Question 11

Earth

Answer 11

Source of Earth’s magnetic field is electric current in the core

Question 12

Earth

Answer 12

Planet’s magnetic field appears related to the planet’s rate of rotation

Question 13

Magnetic field

Answer 13

A stationary charged particle doesn’t interact with a magnetic field, but if moving through a magnetic field, a magnetic force acts on

Question 14

A charged particle moves in a straight line through a region of space. Which of the following answers must be true? (Assume any other fields are negligible.) The magnetic field

Answer 14

Has a ZERO component PERPENDICULAR to the particle’s velocity

Question 15

The north-pole end of a bar magnet is held near a STATIONARY positively charged piece of plastic. The plastic is

Answer 15

Unaffected

Question 16

Charged particle motion in magnetic field

Answer 16

If V IS perpendicular to B creating magnetic force directed toward center of the circle.

Question 17

Charged particle motion in magnetic field

Answer 17

If V IS NOT perpendicular to B particle follows a helical path.

Question 18

As a charged particle moves freely in a circular path in the presence of a constant magnetic field applied perpendicular to the particle’s velocity, the particle’s kinetic energy

Answer 18

Remains constant

Question 19

Magnetic force on current carrying conductor

Answer 19

current up, wire left

Question 20

Magnetic force on current carrying conductor

Answer 20

current down, wire right

Question 21

Magnetic torque

Answer 21

Magnetic forces act on sides with current perpendicular to B

Question 22

Magnetic torque

Answer 22

B at an angle with a line perpendicular to the plane of the loop, torque=BIAsin0

Question 23

A square and a circular loop with the same area lie in the xy-plane, where there is a uniform magnetic field pointing at some angle q with respect to the positive z-direction. Each loop carries the same current, in the same direction. Which magnetic torque is large?

Answer 23

Torque is same

Question 24

Ampere’s Law

Answer 24

NO CURRENT is present in the vertical wire, compass needles point SAME DIRECTION

With STRONG CURRENT, compass needles direct tan to circle pointing in DIRECTION OF B

ELECTRIC CURRENT GENERATES MAGNETIC FIELD

Question 25

Which of the following actions would double the magnitude of the magnetic force per unit length between two parallel current-carrying wires?

Answer 25

Double one current and reduce distance by half

Question 26

Magnetic fields of current loops and solenoids

Answer 26

Magnetic field is in center with n loops Acts as a magnet only when it carries a current N to S