Quiz #4

Match the following conductor insulations with their temperature rating. a. 60°C b. 75°C c. 90°C Type THWN Type THHN Type TW

Type THWN (B 75°C) Type THHN (C 90°C) Type TW (A 60°C)

Low voltage (high voltage drop) in a home can be caused by ____.

a conductor that is to small for the load, a circuit the is too long, or poor connections at the terminals

Type AC cable is manufactured with ____ conductors.

all these types of (two-phase, three-phase, & four-phase)

Under certain circumstances, the grounded (neutral) conductors of a residential service ____ permitted to be sized smaller than the phase conductors.

are

static electricity refers to electrons that ______________ moving.

are not

For a given conductor size, which material has the greatest ampacity?

copper only

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

demagnetized

the regions formed in the molecular structure of magnetic metals are sometimes called magnetic ______________.

domains

What type of magnet depends on flowing current to produce a magnetic field?

electromagnet

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

electron

Insulators are the only materials that can hold _____ stationary.

electrons

Magnetic lines of force are referred to as _____.

flux

electrostatic charges occur on _________.

insulators

If a permanent magnet is cut into pieces, each piece ___ a separate magnet?

is

When a 4 ft. piece of nonmetallic-sheathed cable is used as a fixture whip above an accessible ceiling, it ____.

is not required to be secured

Older texts used the term "MCM" which means the same things as __________.

kcmil

man-made permanent magnets retain their magnetism _________ than natural magnets.

longer

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

magnetite

Bringing a charged test object near the ball of a charged electroscope causes the leaves to move closer together. This indicates that the test object charge is the _____ polarity as the electroscope charge. a. opposite b. same

opposite

The rating of a branch circuit is determined by its ____.

overcurrent protective device (fuse or circuit-breaker)

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

repel;attract

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 semiconductor material used as coating on copy machine drums is _______.

selenium

selenium is a __________.

semiconductor

The National Electrical Code does NOT allow rigid PVC conduit to ____.

support lighting fixtures

The NEC in Table 210.24 shows that the minimum conductor size for branch-circuit wiring is ____.

14 AWG

The total rating of utilization equipment fastened in place, other than luminaires, is not permitted to exceed ____ of the branch-circuit rating if the branch circuit also supplies lighting, other cord-and-plug-connected equipment, or both types of loads.

50%

A dual-rated conductor marked THHN/THWN is rated ____ when used in dry locations.

90°C (194°F)

Connectors marked ____ are suitable for use with aluminum, copper, or copper-clad conductors.

AL/CU only

In which location(s) is Type NM cable NOT allowed to be run?

Both damp and moist locations and when conealed in dry locations

Liquidtight flexible nonmetallic conduit is subject to which of the following limitations?

Both of these choices are limitations -It can become brittle in extremely cold temperatures -It cannot be used in direct sunlight, unless marked for this application

In the English system of measure, magnetic strength is measure in terms of?

Flux density

The three elements that form natural magnets are?

Iron, nickel, cobalt

In the English system, the total force producing a magnetic field is the?

Magnetomotive force

The measure of a materials ability to be magnetized is called?

Permeability

The measure of a materials resistant to magnetism is known as?

Reluctance

The amount of magnetism left in a material after the magnetizing force has been stopped is called?

Residual Magnetism

The NEC requires that conductors 8 AWG and larger must be ____ when installed in a raceway.

Stranded

Type ____ is the most common building wire used today.

THHN/THWN

Earth contains magnetic poles.

True

The ampacity of the conductors in nonmetallic-sheathed cable is based on that of ____ conductors.

60°C (140°F)

The suffix "B" in Type NM-B nonmetallic cable means that the conductors have an insulation temperature rated ____.

90°C (194°F)

Current always flows from positive to negative.

False

An electroscope can be used to determine the polarity of an electrostatic charge.

True

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

ampere-turns

What type of magnets do not require any power of force to maintain their field?

permanent magnets

Branch circuit conductors must have an ampacity ___________ the maximum to be served.

no less than

Conductor sizes up through 4/0 AWG are expressed in American Wire Gauge (AWG). Conductor sizes larger than 4/0 AWG are expressed in ____.

kcmil