DC - Unit 4 Practice Test

In the English system, the total force producing a magnetic field is the _____. a. flux density b. reluctance c. magnetomotive force d. permeability

magnetomotive force

The regions formed in the molecular structure of magnetic metals is sometimes called magnetic _____. a. domains b. atoms c. quarks d. spins

domains

A magnet that produces a magnetic field as long as current is flowing is called a(n) _____ magnet. a. temporary magnet b. electromagnet c. domain magnet d. permanent magnet

electromagnet

The measure of a material's ability to be magnetized is called _____. a. permeability b. reluctance c. saturation d. residual magnetism

permeability

Electrons can form spin patterns that _____ the magnetic field of the material. a. add b. cancel

cancel

The angular difference between true north and magnetic north is known as the angle of _____. a. polarity b. magnetism c. retribution d. declination

declination

If an object is placed in the field of an strong electromagnet connected to an AC line, the object will be _____. a. magnetized b. demagnetized

demagnetized

Magnetism can be explained in terms of _____ spin patterns. a. quark b. neutron c. proton d. electron

electron

In the English system of measure, magnetic strength is measured in a term called _____. a. permeability b. residual magnetism c. flux density d. reluctance

flux density

The three substances that form natural magnets are _____. a. copper, nickel, and boron b. iron, boron, and cobalt c. copper, iron, and cobalt d. iron, nickel, and cobalt

iron, nickel, and cobalt

To locate the north pole of an electromagnet, use the _____ hand rule. a. left b. right

left

Man-made permanent magnets retain their magnetism _____ than natural magnets. a. longer b. less

longer

When a magnetic materials molecules are all lined up, and increases in current flow no longer cause increases in magnetic field strength, the material has reached _____. a. reluctance b. saturation c. residual magnetism d. permeability

saturation

The north magnetic pole of a compass needle is attracted to the _____ magnetic pole of the earth. a. south b. north c. east d. west

south

Lodestone is a name for a naturally occurring magnetic material that is also called _____. a. magnetism b. copper c. lead d. magnetite

magnetite

The measure of a material's resistance to magnetism is _____. a. permeability b. residual magnetism c. reluctance d. saturation

reluctance

The amount of magnetism left in a material after the magnetizing force has stopped is called _____. a. saturation b. permeability c. residual magnetism d. reluctance

residual magnetism

Magnetic lines of force are called _____. a. bands b. flux c. reluctance d. spin

flux

A basic law of magnetism states that unlike poles _____ and like poles _____. a. attract, repel b. repel, attract

attract, repel

_____ do not require any power of force to maintain their field. a. Permanent magnets b. Temporary magnets c. Electromagnets d. Domain magnets

Permanent magnets

The strength of an electromagnet is primarily proportional to its _____. a. core resistance b. length c. diameter d. ampere-turns

ampere-turns