Midterms (Chapter 13. Part 2)

Question 1

the temperature at which a magnetic material loses its ferromagnetic properties.

Answer 1

Curie temperature

Question 2

a classifi cation of materials that become weakly magnetized but in the direction opposite to the magnetizing field. Diamagnetic materials have a permeability less than 1. Examples include antimony, bismuth, copper,
gold, mercury, silver, and zinc.

Answer 2

Diamagnetic

Question 3

a magnet that requires an electric current fl owing in the turns of a coil to create a magnetic field. With no current in the coil, there is no magnetic fi eld.

Answer 3

Electromagnet

Question 4

a nonmetallic material that has
the ferromagnetic properties of iron.

Answer 4

Ferrite

Question 5

a classifi cation of materials that become strongly
magnetized in the same direction as the magnetizing field. Ferromagnetic materials have high values of permeability in the range of 50 to 5000 or even higher. Examples include iron, steel, nickel, and cobalt.

Answer 5

Ferromagnetic

Question 6

the number of magnetic field lines per unit area of a section perpendicular to the direction of flux.

Answer 6

Flux Density

Question 7

the effect that describes a
small voltage generated across the width of a conductor that is carrying current in an external magnetic field. To develop the Hall voltage, the current in the conductor and the external flux must be at right angles
to each other

Answer 7

Hall Effect

Question 8

the electric or magnetic effect of one body on another without any physical contact between them.

Answer 8

Induction

Question 9

another name used to describe magnetic field lines.

Answer 9

Magnetic Flux

Question 10

the cgs unit of magnetic
flux. 1 Mx = 1 magnetic field line.

Answer 10

Maxwell

Question 11

a classifi cation of materials that become weakly magnetized in the same direction as the magnetizing field. Their permeability is slightly more than 1. Examples include aluminum, platinum, manganese, and chromium.

Answer 11

Paramagnetic

Question 12

a hard magnetic material such as cobalt steel that is magnetized by induction in the manufacturing process. A permanent magnet retains its magnetic properties indefinitely as long as it is not subjected to very high temperatures, physical shock,
or a strong demagnetizing field.

Answer 12

Permanent magnet

Question 13

the ability of a material to concentrate magnetic flux.

Answer 13

Relative Permeability

Question 14

an electromagnet wound in the form of a doughnut. It has no magnetic poles and the maximum strength of the
magnetic fi eld is concentrated in its iron core.

Answer 14

Toroid