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