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Electrical Craft Helper Test With
Correct Answers
A molecule of matter can be divided chemically into smaller particles called? - ANSWER atoms
matter consisting of all the same kind of atoms is called an? - ANSWER element
matter consisting of two or more different kinds of atoms is called a? - ANSWER compound
the negative charge of a single electron is called a? - ANSWER unit electrical charge
most of the mass of an atom is in the? - ANSWER nucleus
when an atom gains an electron, it is called? - ANSWER negative ion
copper is a good conductor, because the copper atom loosely holds it's? - ANSWER valence
gold and silver are good conductor of electricity, because the outer orbits have? - ANSWER one electron
when teo negatively charged rods are brought together, they? - ANSWER repel each other
one ampere is equal to? - ANSWER 1 coulomb flowing per second
what happens when two unlike materials are rubbed together and then separated? - ANSWER one will be positive and the other negative
connecting two or more metallic objects with a wire or metal strap is called? - ANSWER bonding
grounding minimizes the voltage difference between an object and? - ANSWER ground
humidity has no effect in controlling a static charge on the surface of? - ANSWER only liquids.
a static charge is generated by liquids when the liquids are? - ANSWER moving and contact other materials
the charges on the surface of a liquid in a container can be made harmless if the container is? - ANSWER purged
greater static charges are developed on smooth surfaced materials than on rough surfaced materials because of the? - ANSWER larger surface contact
what is applied to rubber or that leather belts to prevent the generation of static charges? - ANSWER a conductive dressing
the vest way to remove static electricity from machines is to? - ANSWER ground the framework
dust can be removed from the and in a plant by the use of a? - ANSWER electrostatic precipitation
the six primary methods of producing a voltage are chemical action , magnetism, friction, - ANSWER heat, light, and pressure
electricity is produced by chemical action in a?p - ANSWER storage battery cell
through which of the following do electrons move in storage battery cell? -
what will serve as an effective magnetic shield against magnetic influence - ANSWER an iron or steel casing
what is the MKS unit for magnetic flux - ANSWER weber
the process by which metals are demagnetized is called - ANSWER degaussing
hardened steel is difficult to magnetize demagnetized is called - ANSWER low permeability
what term is often used, instead of voltage, for electrical pressure? - ANSWER wattage
which of the following provides the electrical potential for an electrical system? - ANSWER generator
to measure electrical potential, you should use a? - ANSWER voltmeter
how should a voltmeter be connected in a circuit to measure voltage? - ANSWER in parallel with the potential points being measured
without a given potential, how do free elections in a conductor constantly move? - ANSWER in a random manner
the instrument that measures electrical current is the? - ANSWER ammeter
an ammeter must be connected in the circuit in such a way that? - ANSWER all current flows through it
ghe unit of measuring circuit resistance is the? - ANSWER ohm
ohm's law is used tobdetermine relationships between - ANSWER voltage, current, and resistance
which of the following are used to measure electrical resistance? - ANSWER megohmmeter and ohmmeter
when property of a material is present in every electrical circuit? - ANSWER resistance
resistors are connected to electrical circuits to? - ANSWER limit current
the interaction between the rotor and stator in an A-C motor that causes the rotor to rotate is caused by the? - ANSWER magnetic fields
which of the following materials are most commonly used for electrical conductors? - ANSWER aluminum and copper
a material which has few free electrons, and therefore is a poor conductor, is called a? - ANSWER insulator
what are insulating materials sometimes called? - ANSWER dielectrics
as the current in a conductor increases, the heat it generates in the conductor increases? - ANSWER as the square of the current increase
what is the definition of a circular mil? - ANSWER the standard unit of measurement for wire cross-sectional areas
dielectric strength is usually expressed in terms of? - ANSWER volts
in simplified terms, what does ohms law state? - ANSWER the higher the resistance in the conductor, the more current in the line for the same voltage
desirable characteristics of conductor insulation include? - ANSWER flexibility and mechanical strength
a channel that holds and protects wirs or cables is known as a? - ANSWER race way
BX cable has the same general characteristics as? - ANSWER flexible conduit
electrical current is measured in amperes, which are? - ANSWER coulombs -per-second
according to ohms law, voltage is equal to? - ANSWER resistance times current
what happens to total current flow if the voltage of a series circuit is doubled and the resistance stays constant? - ANSWER doubles
how many paths for current flow will there be in a series circuit that has five resistors? - ANSWER one
in a Delta connected load or source the line voltage is found by what formula? - ANSWER EL = Ep
the formula for finding the line current in a Delta connected load or sources - ANSWER IL = √3Lp
and either a y or Delta connected load what is the power per phase at 480 volts 50 amperes and 75% power factors P Ep Ip cos 0 - ANSWER 18, watts
in either a y or Delta connected load what is the three phase power in Watts at 240 volts 20 amperes and 8% power factor
P=√3EL IL Cos 0 - ANSWER 6,643 watts
the Greek letter for Delta is - ANSWER ∆
the Cos 0 used in 3 phase power formulas is the - ANSWER power factor
one method of measuring power in a 3-phase circuit is by the use of - ANSWER 3 wattmeters
measuring the power of a 3-phase circuit at 50% power factor using only to 2 watt meter, 1 wattmeters will read - ANSWER zero power
to which transformers wending is voltage supplied - ANSWER primary
switch transformer winning is load connected - ANSWER secondary
a transformer has 400 turns in the primary and 200 turn to the secondary at 240 volts are applied to the primary winding what voltage will be measured on the second winding - ANSWER 120 volts
the volt amperes of the primary winding and the volt-amperes of the secondary winding in a transformer are - ANSWER equal
the output of capacity of a transformers is rated in - ANSWER KVA
transformers losses are classified as copper losses and - ANSWER cross losses
transformers core eddy current losses are reduced by using a - ANSWER laminated core
voltage windings in diagram below two secondary windings are connected in
