Circuit - ANSWERis a complete path (when ON) for current to take that includes electrical control devices, circuit protection, conductors, and load(s)
static electricity - ANSWERis an electrical charge at rest
semiconductor - ANSWERis an electronic device that has electrical conductivity betw...
EXAM #2 CMGT 235 Questions &
Answers(RATED A)
Circuit - ANSWERis a complete path (when ON) for current to take that includes
electrical control devices, circuit protection, conductors, and load(s)
static electricity - ANSWERis an electrical charge at rest
semiconductor - ANSWERis an electronic device that has electrical conductivity
between that of a conductor (high conductivity) and that of an insulator (low
conductivity)
if a fire should occur, the first thing an individual must do is _______ -
ANSWERprovide an alarm
Ground Fault Circuit Interrupter (GFCI) - ANSWERis a fast-acting receptacle that
detects low levels of leakage current to ground and opens that circuit in response to
the leakage
Class A - ANSWERfires that are typically controlled with water
dry powdered compound - ANSWERextinguishing agent for class D
Before connecting a tool to a power source, ensure that the on/off switch is in the
_________ position - ANSWEROFF
circuit breaker - ANSWERis an over current protection device with a mechanical
mechanism that may manually or automatically open a circuit when an overload
condition or short circuit occurs
time-delay plug - ANSWERfuse is a screw-in type electrical safety device with a dual
element
A semiconductor is any material that has a very high resistance and resists the flow
of electrons - ANSWERFalse
Electrical tool pouch - ANSWERA small, open tool container (pouch) for storing
commonly used electrical tools
Transformer - ANSWERAn electric device that uses electromagnetism to change
(step-up or step-down) AC voltage from one level to another
The broad categories of fuses are _______ - ANSWERPlug, cartridge, and blade
An equipment ground is a circuit designed to protect individual components
connected to an electrical system - ANSWERTrue
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Conductors have five or more valence electrons - ANSWERFalse
Never wear safety goggles or a dust maskwhen using power tools - ANSWERFalse
Electricity is the movement of electrons from atom to atom - ANSWERTrue
Fuse - ANSWERAn electronic overcurrent protection device used to limit the rate of
current flow in a circuit
Five common classes of ________ are Class A, Class B, Class C, Class D, and
Class K - ANSWERFires
Valence Shell - ANSWERThe outermost shell of an atom and contains the electrons
that form new compounds
Service Panel - ANSWERAn electrical device containing fuses or circuit breakers for
protecting the individual circuits of a residence and serves as a means of
disconnecting the entire residence from the distribution system
A standard plug fuse is a screw-in type electrical safety device that contains a metal
conducting element designed to melt when the current through the fuse exceeds the
rated value - ANSWERTrue
Personal Protective Equipment (PPE) - ANSWER
Air Velocity - ANSWERthe speed at which air moves from one point to another. p402
Duct Size - ANSWERsize of a duct, expressed in inches diameter for round ducts
and in inches of width and height for rectangular ducts. p403
Friction Loss - ANSWERthe decrease in air pressure due to the friction of the air
moving through a duct. p403
Static Pressure - ANSWERair pressure in a duct measured at right angles to the
direction of air flow. p403
Static pressure drop - ANSWERthe decrease in air pressure cause by friction
between the air moving through a duct and the internal surfaces of a duct. p403
Manometer - ANSWERa device that measures the pressures of vapors and gases.
p.403
Inclined Manometer - ANSWERa U-tube manometer designed so the bottom of the
"U" is a long inclined section of glass or plastic tubing. p403
U-tube Manometer - ANSWERa U-shaped section of glass or plastic tubing that is
partially filled with water or mercury. p403
Design static pressure drop - ANSWERthe pressure drop per unit length of duct for a
given size of duct at a given air flow rate. p404
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Equal friction chart - ANSWERa chart that shows the relationship between the air
flow rate, static pressure drop, duct size, and air velocity. p404
System pressure drop - ANSWERthe total static pressure drop in a system. p405
Major duct section - ANSWERan independent part of a forced-air distribution system
through which all or part of the air supply from the blower flows. p405
Individual duct section - ANSWERpart of a distribution system between fittings in
which the air flow, direction, or velocity changes due to the configuration of the duct.
p405
Dynamic pressure drop - ANSWERthe pressure drop in a duct fitting or transition
caused by air turbulance as the air flows through the fitting or transition. p406
Table of equivalent lengths - ANSWERa table used to convert dynamic pressure
drop to friction loss in feet of duct. p406
Layout drawings - ANSWERdrawings of the floor plan of a building that show walls,
partitions, windows, doors, fixtures, and other details. p407
Single line drawing - ANSWERdrawing in which the walls and partitions are shown
by a single line with no attempt to show actual wall thickness. p408
Double line drawing - ANSWERWalls and partitions are shown with double lines.
Wall thickness is shown at actual scale on the drawing. p408
Duct section - ANSWERsection of ductwork between two fittings where air flow rate
changes. p408
Equal friction method - ANSWERduct sizing that considers that the static pressure is
approximately equal at each branch takeoff in the distribution system. p409
Aspect ratio - ANSWERratio between the height and width of a rectangular duct.
p410
Velocity reduction method - ANSWERduct sizing that considers that the air velocity
is reduced at each branch takeoff. p410
Static regain method - ANSWERduct sizing that considers that each duct section is
sized so that the static pressure increase at each takeoff offsets the friction loss in
the preceding duct section. p410
Equal velocity method - ANSWERduct sizing that considers that each duct section
has the same air velocity. p411
Free area - ANSWERof a register is the face area of the register minus the area
blocked by the frame or vanes. p415
3 / 4
Fittings and transitions are duct sections that change air flow direction or duct size -
ANSWERTRUE
Measuring static pressure without first measuring velocity pressure is difficult. -
ANSWERFALSE
The equal velocity method is more applicable to sizing exhaust systems or material
collection systems than it is for sizing distribution ducts for a heating or air
conditioning system. - ANSWERTRUE
___ pressure drop is the pressure drop in a duct fitting or transition caused by air
turbulence as the air flows through the fitting or transition. - ANSWERDYNAMIC
Friction gain occurs as air scrubs against the internal surfaces of a duct. -
ANSWERFALSE
The air velocity at a register determines the distance the air is thrown from that
register. - ANSWERTRUE
___ flow rate of air is the quantity of air moved per unit of time. -
ANSWERVOLUMETRIC
Fitting loss coefficients are values that represent the ratio between the total static
pressure loss through a fitting and the dynamic pressure at the fitting. -
ANSWERTRUE
For a combination heating and cooling system the larger air flow rate is used for duct
sizing. - ANSWERTRUE
To find the static pressure loss for a duct section, the total equivalent length of the
duct section is divided by ___¢ and multiplied by the design static pressure drop that
was used to size the duct. - ANSWER100
Conventional load calculations are performed manually - ANSWERtrue
the information for the heating load is entered on the form first because more data is
required for calculating heating loads than for cooling loads - ANSWERfalse
a winter indoor design temperature of 75 degrees F is usually selected to provide
comfort for a normally clothes person during winter - ANSWERfalse
design temperature difference is the difference between the indoor design
temperature and the outdoor design temperature - ANSWERtrue
plans are drawings of a building that show dimensions, construction materials,
location, and arrangement of the spaces within a building - ANSWERtrue
hallways, closets, stairways, and other spaces in a building not part of a room or
zone are included in the dimensions of adjacent rooms or zones - ANSWERtruePowered by TCPDF (www.tcpdf.org)
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