term 1 exam
What is the kW of a 75W load?
0.075 kW
The decimal equivalent for the fraction "4/18" is _____.
0.20
"Root-mean-square" is the value equal to _____ of the of the amplitude of a measured value.
0.707
The decimal equivalent for "75 percent" is _____.
0.75
What is the reciprocal of 1.25?
0.80
What is the maximum distance that two 14 AWG conductors can be run if they carry 16A and the maximum allowable voltage drop is 10V?D = (Cmil x VD)/(2 x K x I)D = (4,110 cmil x 10V)/(2 x 12.90 ohms x 16A)
100ft
The output power of a transformer is 100W and the transformer efficiency is 90 percent. What is the transformer input if the output is lower than the input? Formula: Input = Output/Efficiency
110W
The numeric equivalent of 122 is _____.
144
The decimal equivalent for "225 percent" is _____.
2.25
An overcurrent protection device (breaker or fuse) must be sized no less than 125 percent of the continuous load. If the load is 16A, the overcurrent protection device will have to be sized at no less than _____.
20A
What is the volume (in cubic inches) of a 4 x 4 x 1.50 in. box?
24 cu. in.
What is the area in sq in. of a trade size 2 raceway? Formula: Area = Pi x r2, Pi = 3.14, r = radius (1/2 of the diameter).
3 sq. in.
An electric arc blast can approach _____, which vaporizes metal parts and produces an explosive and deadly pressure wave.
30,000°F
What is the current in amperes of an 18kW, 208V, three-phase load?Current: I = VA/(E x Ö3) Current: I = 18,000W/(208V x 1.732)
50A
What is the power consumed in watts by a 12 AWG conductor that is 100 ft long and has a resistance (R) of 0.20 ohms, when the current (I) in the circuit is 16A? Formula: Power = I2 x R.
50W
The maximum continuous load on an overcurrent protection device is limited to 80 percent of the device rating. If the overcurrent device is rated 100A, the maximum continuous load is _____.
80A
The feeder calculated load for an 8 kW load, increased by 20 percent is _____.
9.60 kW
Compounds can change the electrical characteristics of an individual atom. For example, the insulating aluminum-oxide compound is very difficult to break and it often results in the overheating of aluminum conductors at their terminals.
True
To change a percent value to a decimal or whole number, drop the percentage sign and move the decimal point two places to the _____.
left
The minimum and maximum quantity that a DMM can safely and accurately measure is known as the "_____ range."
measuring
The method of increasing a number by another number is done by using a _____.
multiplier
"_____" is defined as the rate of work measured by the unit called the watt.
power
An advanced DMM can be used for standard DMM applications, troubleshooting complex problems, and identifying conditions that lead to _____.
problems
To prevent corrosion from forming on low-voltage electronic circuitry connectors, _____ plating is often placed on copper cable terminals.
silver or gold
DMMs commonly use _____ to represent a quantity or term for quick recognition.
standard abbreviations
A standard DMM is useful for _____.
taking measurements troubleshooting Correct! a and b
Because the attractive force of the protons is greater on electrons that are closest to the nucleus, electrons in the orbits farthest away from the nucleus are more easily separated from their atomic structure.
te
Characteristics of a general-purpose DMM include _____.
the ability to measure two or more basic electrical quantities a continuity test mode a display usually limited to three digits Correct! all of these
"Electroplating" is building up layers of metal on one surface by removing the same metal from another surface by a chemical action with electric current in a solution.
true
A battery is a power source where voltaic cells are combined in a series arrangement, positive terminal to negative terminal, so that the voltage of one cell is added to the voltage of the other cells.
true
According to the Conventional Current Flow Theory, a positive charge flows from positive to negative in the circuit.
true
According to the Electron Current Flow Theory, electrons flow away from the negative terminal of the source, through the circuit and load, toward the positive terminal of the source.
true
Atoms strive for chemical stability, which is the condition where the valence shell is completely filled. This is often accomplished by combining atoms together to produce a compound atom.
true
Conductive materials have one, two, or three valence electrons. Elements with one valence electron, such as silver, copper, and gold, make the best electrical conductors.
true
DC power is determined by multiplying the electromotive force by the circuit intensity.
true
Fluorescent lighting is illumination that results from the combination of electroluminescence and phosphorescence.
true
Hard steel will retain a relatively large amount of its magnetism, but it does not have the magnetic strength of soft iron.
true
If a conductor carrying current is next to another conductor carrying current in the opposite direction, the electromagnetic field attempts to pull the conductors apart.
true
If a conductor is twisted to form a loop, the electromagnetic fields around the conductor are compressed to create a dense and strong electromagnetic field.
true
If a permanent magnet is struck with a hammer, it will lose some of its magnetism; each subsequent blow helps the molecules return to their original random positions.
true
If conductor loops are wound in the same direction, the conductor's electromagnetic fields add together.
true
Moving a magnetic field through a conductor provides the energy needed to cause the valence electrons in the conductor to flow in a given direction.
true
Permeability describes the relative ease with which a material can be magnetized.
true
Photoelectricity is the principle that photons striking a semiconducting plate cause the plate to release electrons to another semiconducting plate.
true
Power is not equal to E x I for ac circuits because consideration must be given to inductive reactance.
true
Smaller conductors have greater resistance and larger conductors have lower resistance.
true
Soft iron can be used to make a stronger magnet than hard steel, but the instant the magnetizing force is removed, the soft iron loses practically all of its magnetism.
true
Soft iron has high permeability, whereas hard steel is hard to magnetize, which means it has low permeability.
true
Some crystalline materials produce a small electrical voltage when bending or twisting pressure is applied to them. This is called "piezoelectricity."
true
Squaring a number means multiplying the number by itself.
true
The attraction between the positive charge of the protons and negative charge of electrons keeps the electrons from breaking out of their orbit.
true
The electromagnetic field of a coil can be made stronger by placing a soft iron core inside the coil windings.
true
The strength of an electromagnetic field dependents on the magnitude of the current and the number of turns in the electromagnet coil.
true
The work that can be performed by the moving electrons dependents on the circuit pressure and the circuit's opposition to the flow of electrons.
true
When conductors carrying current in the same direction are brought together, the electromagnetic fields attempt to push the conductors together.
true
When energy is applied to the valence electrons, the energy is distributed evenly among all the valence electrons.
true
When magnetized material keeps its magnetic field for a long time, it is a permanent magnet. Hard iron or steel is used for permanent magnets.
true
A DMM is commonly used for measuring electrical quantities such as _____ in electrical and electronic circuits.
voltage amperage resistance Correct! all of these
Electrical pressure is called "_____," and it is measured in Volts.
EMF potential Correct! a or b none of these
The outermost shell is called the "valence shell" and electrons in this shell are called "valence electrons." The maximum number of electrons in the valence shell is _____.
Eight
Semiconductors contain more than six valence electrons
Flase
The term "_____" refers to a decrease in the amplitude of a signal.
attenuation
The volume of an enclosure is expressed in _____, and it is calculated by multiplying the length, by the width, by the depth of the enclosure.
cubic inches
Aluminum has a lower resistance to the flow of electrons than does copper.
false
Deriving the square root of a number is almost the same as squaring a number.
false
Every component of an electrical circuit contains resistance, except the power supply.
false
Ferrous metals do not contain any iron and therefore cannot be magnetized.
false
Insulators have four to five valence electrons.
false
Magnetic lines of force can cross each other.
false
The Law of Attraction and Repulsion of magnets states, "Like poles attract and unlike poles oppose each other."
false
The direction of the electromagnetic field around a conductor because of current flow is determined by the right-hand rule as it relates to electron theory.
false
The end of the magnet that points to the north is called the "south-seeking pole," and the opposite end of the magnet is the "north-seeking pole."
false
The field intensity around a conductor carrying current decreases with increased current flow, and is stronger the further the distance from the conductor.
false
The movement of electrons to perform a useful function is called "static electricity."
false
The time it takes for an overcurrent protection device to open is directly proportional to the magnitude of the fault current.
false
To force electrons to move, some form of energy must be applied to the electrons to cause them to leave their atom. This energy can only be supplied by magnetism.
false
When electrons are forced to move through a conductor, the magnetic fields of individual electrons subtract from one another.
false
The "trigger level" is the _____ level at which the DMM counter is triggered.
fixed
DMMs can be broadly classified as _____ DMMs.
general-purpose standard advanced Correct! any of these
