Steam & Hydronics
The basic unit use to measure a quantity of heat is the ________ a. degree celcius b. British thermal unit c. degree Kevin d. degree Fahrenheit
British Thermal unit
A high head pump is a pump classified as above _____ hp and operating above 12' of pressure head. a. 1/4 b. 1/3 c. 1/2 d. 2/3
1/2
In northern climates, low-temperature limit switches are installed that force dampers to close and activate the heating system to _____% when the outdoor low-temperature limit is reached. a. 70 b. 80 c. 90 d. 100
100
Wet-bulb temperature is the temperature of air if it were cooled to _____% RH. a. 25 b. 50 c. 75 d. 100
100
A low-pressure water heating boiler is a boiler in which water is heated for the purpose of supplying hot water with a MAWP of not more than ______psi. a. 30 b. 60 c. 100 d. 160
160
What is the maximum design pressure for a low temperature boiler (ASME)? a. 160psig b. 180psig c. 210psig d. 250psig
160psig
In a hydronic system, boiler water temperature is usually maintained at _______ so heat can immediately delivered to the tank. a. 100F to 120F b. 120F to 140F c. 150F to 170F d. 180F to 200F
180F to 200F
Bacterial growth can occur in hydronic systems, especially low-temperature systems that are not properly installed or where glycol-water mix ratio is below _______%. a. 5 b. 10 c. 20 d. 40
20
Many of the hydronic system components, such as the pump, the expansion tank, and the motorized valves, should last about _____ years. a. 2 b. 10 c. 20 d. 35
20
If the space above a ceiling radiant panel is unconditioned, the minimum R-value is R-______. a. 10 b. 30 c. 65 d. 95
30
The hydronic cooling system is composed of _________ separate and distinct cycles that create the complete system. a. 2 b. 3 c. 4 d. 5
5
According to ANSI/ASHRAE guidelines, an AHU mounted horizontally should not have a coil-face airflow velocity of more than _____fpm. a. 300 b. 500 c. 850 d. 1000
500
Glycol concentrations up to about ______% can be checked with a refractometer or glycol test kit. a. 25 b. 55 c. 80 d. 95
55
A ROT (rule of thumb) can be used to calculate fill pressure of a hydronic system; when using the ROT what is considered a standard height per floor? a. 8 b. 10 c. 12 d. 15
8
Generally, for a two-pipe system, the connections to risers, branches, or terminal units are taken off the top of the main at either a 45* or _____ angle from the horizontal plane. a. 50* b. 70* c. 90* d. 100*
90*
______ is the leading international developer of codes and standards associated with the art, science, and practice of mechanical engineering. a. American society of mechanical engineers (ASME) b. American society for testing and materials (ASTM) c. American water works association (AWWA) d. Canadian standards association (CSA) group
American society of mechanical engineers (ASME)
What does the ASME Boiler Pressure Vessel Code require if the output of a boiler is 400,000 Btuh or more? (C5 TEST) a. makeup water b. chemical pot feeder c. LWCO d. wet rotor pump
LWCO
______ are powered by electricity and use refrigerants to cool the air. a. fans b. electric pumps c. air conditioners d. radiant panels
air conditioners
Fuel oil burners _________ fuel oil to increase contact with combustion air for maximum efficiency. a. stabilize b. mix c. atomize d. heat
atomize
What device is used to protect a potable water system from cross connections? a. circuit setter b. backflow preventer c. pressure relief valve d. isolation valves
backflow preventer
When preparing to start a hydronic system for the first time, review the job specifications to determine the testing, ______, and adjusting work required and the requirements for reporting the results. a. balancing b. inspecting c. pressurizing d. charging
balancing
Select the correct valve that would be used to regulate the rate of HTF flow in a piping system. a. check valve b. isolation valve c. gate valve d. balancing valve
balancing valve
The_____ in a cabinet unit eater adds energy to the air so that directional louvers can be used on the top or front of the heater to distribute the air more efficiently in a building space. a. blower b. filter c. HTF coil d. booster coil
blower
Which type of device is attached to the boiler to assist in the management of air in the hydronic system? a. aquastat b. relief valve c. boiler fitting d. LWCO
boiler fitting
A _______ pressure gauge is a mechanical pressure gauge with a curved tube made of thin metal that acts as a pressure-sensing element. a. schrader b. vacuum c. spring-loaded d. bourdon tube
bourdon tube
_____ is the flashing of pumped liquid into vapor bubbles and the subsequent violent collapsing of those bubbles as the liquid moves from suction to discharge through the pump. a. pitting b. bubbling c. cavitation d. corrosion
cavitation
A _____ valve is a valve that permits fluid flow in only one direction and closes automatically to prevent backflow. a. ball b. gate c. balancing d. check
check
A _____ has many of the same components as an end-suction flexibly coupled pump but does not employ a pump shaft or pump bearing assembly. a. close-coupled end-suction pump b. circulator c. small in-line pump d. single suction pump
close-coupled end-suction pump
A __________ impeller is an impeller that has shrouds on both sides of the vanes. a. open b. closed c. semi open d. primed
closed
A modern hydronic system is almost exclusively a (n) _______ system, force circulated by a pump or circulator. a. closed b. gravity c. open d. combustion
closed
A(n) _____ control system is a control system in which the result if an output is fed back into a controller as an input. a. feedforward b. closed-loop c. time-based d. open-looped
closed-loop
_____ is a formal assessment of the functionality and efficiency of a system. a. balancing b. inspecting c. commissioning d. measuring
commissioning
Name the four main components of a chiller system a. pump, air tank, HTF, pipe, boiler b. compressor, condenser, evaporator, refrigerant c. piping, refrigerant, compression tank, pump, thermal unit d. radiant slab, compressor, condenser, piping
compressor, condenser, evaporator, refrigerant
Which type of boiler uses microprocessor-controlled combustion which automatically adjusts air-fuel mixture? a. cast iron b. condensing c. scotch marine d. steel tube
condensing
A(n) ______ is a changing characteristic used to communicate system information between control devices. a. control signal b. solenoid c. relay b. electric loop
control signal
Radiant panels release 50% to 70% of their heat to a room by radiation and provide the balance of the heat by ___. a. conduction b. convection c. enthalpy d. perspiration
convection
________ is the transfer of heat in which heat is moved from one location to another through the circulation of a fluid, such as air or water. a. convection b. conduction c. radiation d. evaporation
convection
A_____ valve changeover is the most commonly used changeover method using two three-way valves connected to the terminal unit or zone piping on a four-pipe system. a. convectional three-way b. standard three-way c. conventional two-way d. standard two-way
convectional three-way
What type of flow has better heat transfer in a coil? a. parallel flow b. counterflow c. upward flow d. downward flow
counterflow
As total head increases, pump flow rate _____. a. decreases b. is not affected c. increases d. balances
decreases
______ may be caused by excessive velocity present in a piping system. a. erosion b. fatigue stresses c. pitting d. scale
erosion
______ control the process that calculates the actual start time for system equipment based on building temperature data and a thermal recovery coefficient. a. optimum start b. estimation start time c. adaptive start time d. thermal recovery
estimation start time
Of the two types of glycols used in hydronic systems, _______ glycol has better heat transfer characteristics, but it is more hazardous to handle during preparation. a. benzene b. ethylene c. xylene d. propylene
ethylene
In a comparison refrigeration system, where is the heat absorbed? a. evaporator b. compressor c. condenser d. metering device
evaporator
A(n) ____ is a special fitting made for installation at any convenient point along a long run of pipe for the purpose of absorbing expansion and contraction. a. contraction joint b. expansion joint c. expansion loop d. contraction loop
expansion joint
A____ is intended to supply air only to the room where it is located. a. heat pump b. fan coil unit c. four-pipe system d. gravity hydronic loop
fan coil unit
A _____ convection unit is a convection terminal unit that creates convective currents by mechanically moving air past a terminal unit element. a. baseboard b. cabinet c. radiant d. forced-air
forced-air
A compression tank performs ___ important function(s) in a hydronic system. a. one b. two c. three d. four
four
A_____-pipe system is used where each terminal unit or zone may heat or cool independently of all other units or zones. a. one b. two c. three d. four
four
The common piping length should be as short as possible and not more than _____ pipe diameters apart. a. four b. five c. six d. seven
four
There are ____ types of hydronic heating forced-air convection units. a. three b. four c. five d. six
four
A ______ valve is a valve used to control fluid flow by means of a pliable disc that is compressed against a valve seat surrounding the opening through which water flows. a. globe b. gate c. ball d. three-way
globe
Static pressure in a closed hydronic system ________ pump capacity. a. has no effect on b. increases c. balances d. decreases
has no effect on
as chilled water temperatures increase, less moisture condenses out of the air, and the RH _________. a. decreases b. increases c. balances d. remains unaffected
increases
A(n) _____ control algorithm is a control algorithm in which the output is determined by the sum of the offset over time. a. proportional b. derivative c. integral d. proportional/integral/derivative
integral
In most cases, a cooling system will reduce the humidity levels in a space by removing the _____ heat of the moisture in the air. a. specific b. excess c. latent d. sensible
latent
The most common application of _______ control is the control of multiple hot water or chilled water pumps. a. high-limit b. setpoint c. lead/lag d. averaging
lead/lag
_____ control functions have the highest priority of all control functions. a. scheduled b. duty c. optimum start/stop d. life safety
life safety
Generally, on small systems where the pumps do not produce more than 12' of head, pump ______ may not be important. a. temperature b. pressure c. location d. flow direction
location
Select the best description of a LWCO: a. low water circulator b. little water cut off c. less water control operator d. low water cut off
low water cut off
System maintenance should include a _____ inspection of piping and HTF by the property owner or facility manager. a. daily b. weekly c. monthly d. yearly
monthly
Far less water than air is needed to distribute the same amount if heat, meaning that hydronic water distribution can use piping that is ______ the equivalent air ductwork. a. much larger than b. the same size as c. much smaller than d. unrelated to
much smaller than
A ____ hydronic system is used where the terminal units, such as unit heaters and convection units for heating and cooling, have very high pressure drops. a. one-pipe b. two-pipe c. three-pipe d. four-pipe
one-pipe
A ________ hydronic system is a piping system that is exposed to atmospheric pressure at some point within the system. a. closed b. static c. dynamic d. open
open
A water loop system circulates water from the chiller condenser to the cooling tower and back to the chiller condenser and is typically a(n) _______ system. a. gravity b. open c. closed d. combination
open
A(n) _____ control system is a control system in which decisions are made based only on the current state of the system and a model of how it should work. a. closed-loop b. back-loop c. open-loop d. time-loop
open-loop
The most common method to slow or eliminate the passage of ______ across a tubing wall is to apply a thin layer of oxygen resistant polymer to the tubing. a. nitrogen b. water c. carbon dioxide d. oxygen
oxygen
______ within a hydronic piping system can cause or accelerate the corrosion of pipe, fittings, and system components. a. propylene b. oxygen c. water d. ethylene
oxygen
A ____ radiator is a radiator designed to function more efficiently and at lower HTF temperatures than a traditional radiator. a. baseboard b. finned tube c. panel d. radiant baseboard
panel
In____ is when two or more circuits or branches have a common starting and ending point. a. combination b. conjunction c. unison d. parallel
parallel
A distribution system includes __________. a. piping and fittings to transport the HTF b. a boiler and other heat source to heat the HTF c. a heat exchange element d. a pump or circulator to forcibly move the HTF through the system
piping and fittings to transport the HTF
The most common type of airflow station is a ______ station. a. hot wire anemometer b. pitot anemometer c. hot wire tube d. pitot tube
pitot tube
A diversion fittings is a fitting that creates a greater-than-normal ____ in a line in order to divert flow to another line. a. temperature drop b. pressure drop c. temperature spike d. pressure spike
pressure drop
Select the devices which would be included in a make-up water system. a. pressure relief, backflow, isolation b. balancing valve, backflow, isolation c. flow control, backflow, isolation d. pressure reducing valve, backflow, isolation
pressure reducing valve, backflow, isolation
_______ maintenance is scheduled and unscheduled work required and expected to keep equipment in peak operating condition. a. corrective b. predictive c. prescriptive d. preventive
preventive
The ____ circuit or loop is the piping directly connected to the heat source or chiller inlet and outlet and to which the compression or pre-charged expansion tank is connected. a. primary b. secondary c. tertiary d. central
primary
______ pumping is a means of interconnecting piping circuits so that the operation of one will not affect the other. a. primary-secondary b. parallel c. secondary-tertiary d. series
primary-secondary
Ethylene glycol-based fluids are less viscous than ______ glycol-based fluids and therefore generally provide superior heat transfer efficiency and better low-temperature performance. a. xylene b. propylene c. styrene d. benzene
propylene
A(n) ______ is a set of rules and procedures for the exchange of information between two connected devices. a. algorithm b. sequence of operations c. protocol d. control strategy
protocol
Since the greatest amount of body heat is lost by ________, it is logical that the system most satisfactorily controls this loss is best able to create a comfort condition. a. conduction b. convection c. zoning d. radiation
radiation
A ____ valve is a hydronic piping system monitoring device that is equipped with an integral check valve designed to minimize system fluid loss when setting up to monitor pumps, heat exchangers, valves, or other devices handling hot or cold HTF. a. balancing b. readout c. flow-control d. lift
readout
A(n) _____ of conditioned spaces below 30% tends to reduce moisture levels in occupants, which can result in respiratory infections, dry skin, and general discomfort. a. relative humidity b. air temperature c. gauge pressure d. atmospheric pressure
relative humidity
Which device protects the boiler from pressures above maximum design pressure? a. check valve b. balancing valve c. relief valve d. gate valve
relief valve
_______ control is a control strategy in which a primary setpoint is adjusted automatically as another value changes. a. low-limit b. Setback c. high/low signal select d. reset
reset
Low-pressure steam heating boilers are the most commonly used boilers for ______ steam heating systems. a. power b. process c. industrial d. residential
residential
A tee-shaped fittings is a carefully engineered device which introduces just the right amount of ____ to ensure a proper diversion of HTF to terminal units. a. resistance b. power c. pressure d. heat
resistance
A (n) _____ clamp is a two-piece clamp used to support vertical runs of steel pipe, cast-iron pipe, and copper tube. a. pipe strap b. beam c- c. riser d. pipe saddle
riser
In the _____ method, subfloor spacers or sleepers separate the tubing and suspend the finished flooring above the tube. a. surface-mounted b. manufactured radiant panel c. sandwich d. preformed panel
sandwich
Heat that causes change in temperature that can be measured is _____ heat. a. specific b. latent c. vaporized d. sensible
sensible
The _____ output signal is commonly electrical, such as voltage or current. a. function b. device c. control d. sensor
sensor
The optimum outcome of a control strategy is one that fulfills the requirements of the_______, such as maintaining a comfortable indoor environment or providing adequate lighting, while minimizing energy use, manual interaction, and equipment wear and tear. a. sequence of operations b. protocol c. setpoint d. offset
sequence of operations
A ____ system is a piping system that circulates HTF through a single main in which each terminal unit serves as a portion of the main. a. single main b. series main c. series loop d. single loop
series loop
The most commonly used panel tubing arrangement is the _____ coil method. a. cross-linked b. stacked c. spiral d. serpentine
serpentine
The ______-based method is considered inaccurate and unreliable and is used only in limited cases and as a last resort. a. temperature b. gpm c. pressure drop d. velocity
temperature
The difference between the draw-through and blow-through AHU fan types is in the _____ of air produced by the unit. a. speed b. pressure c. temperature d. volume
temperature
______ sensors are the most common inputs used in hydronic control systems. a. pressure b. temperature c. flow d. differential
temperature
hydronic heating and cooling is efficient because the ________ of water circulating through the system is automatically increased or decreased to meet varying weather condition. a. temperature b. amount c. pressure d. speed
temperature
As a vapor is compressed in a comparison refrigeration system what happens to the refrigerant? a. temperature increases b. converts to a liquid c. condenses d. pressure decreases
temperature increases
When a heat pump is in cooling mode, the outdoor device is ________. a. the evaporator b. the condenser c. the 4 way valve d. the compressor
the condenser
A _____ control valve is a silent, efficient, nonelectric control valve that provides reliable temperature control for a hydronic terminal unit. a. check b. thermostatic c. zone d. drain
thermostatic
A typical modern hydronic heating and cooling system is divided into ______ main parts. a. two b. three c. four d. five
three
Air can exist in ______ distinct forms within hydronic heating and cooling systems. a. two b. three c. four d. five
three
All matter is considered to exist in one of _______ states. a. two b. three c. four d. five
three
If a terminal unit has ______ -way thermostatically controlled valves with bypasses, a two-step balance is required. a. two b. three c. four d. five
three
PEX-AL-PEX is a composite tubing made of _____ layers. a. two b. three c. four d. five
three
There are _____ types of building maintenance programs. a. two b. three c. four d. five
three
A _____ is a device that converts one form of energy into another. a. transducer b. pressure transmitter c. thermowell d. flow switch
transducer
________ valves are quietly operating heavy-duty valves that perform all the functions normally required on the discharge side of the hydronic system pumps. a. straight-angle b. triple duty c. double duty d. side angle
triple duty
The ____ line is the section of the main in a multiple circuit system that carries the combined capacity of the circuits. a. branch b. primary c. main d. trunk
trunk
The major difference between copper tube and copper pipe is the method of sizing, since ______. a. tubing cannot be threaded b. piping cannot be threaded c. piping depends on the outside diameter d. tubing depends on the tube schedule
tubing cannot be threaded
A recommended grout mixture is one part cement to ______ parts clean, sharp sand, wet enough to flow freely. a. one b two c. three d. four
two
A single loop system can serve ____ circuits. a. one b. two c. three d. four
two
In a correctly designed ____-pipe system, the pressure in the supply main is higher than that in the return main, and a slight variation in the distances of the supply and return connections from the heat source is usually not an important factor. a. one b. two c. three d. four
two
There are ____ types of terminal units commonly used in hydronic heating systems. a. two b. three c. four d. five
two
There are _____ types of pump misalignment that must be checked for. a. two b. three c. four d. five
two
There are _________ basic classifications of pumps. a. two b. three c. four d. five
two
A_____ heater is a self-contained, forced-air convection heater that is not connected to ductwork and contains a fan, an HTF coil, and controls in one cabinet. a. kick space convection b. cabinet unit c. foil coil unit d. unit
unit
Temperature is the indirect measure of the _______ attained by the molecules in a substance and is a measure of the intensity of heat. a. density b. mass c. velocity d. depth
velocity
A(n) _____ is a control point that does not correspond to a physical sensor or actuator but exists only in software. a. setpoint b. dead band c. offset d. virtual point
virtual point
A ______ is the pump casing or body that contains the pumped HTP under pressure. a. motor b. impeller c. volute d. diffuser
volute
Metal piping may be tested with either water or air, but plastic piping must be tested with ______. a. coolant b. air c. oil d. water
water
A ____ is a section of a building that is controlled by one HVAC controlling device. a. zone b. territory c. sector d. domain
zone
Thermal insulation for a snow- and ice-melt system should have a minimum R-_____ value and be resistant to water absorption. a. 1 b. 3 c. 5 d. 7
1
An output rating is the total amount of heat a boiler will produce in ________. a. 1 hour b. 30 minutes c. 24 hours d. 1 year
1 hour
In the _____ air separator, system piping is connected to tangential nozzles that are used to create a vortex in the center of a cylindrical vessel. a. Watts series AS Air Scoop b. Bell & Gossett Rolairtrol c. Bell & Gossett Airtrol d. Caleffi Discal
Bell & Gossett Rolairtrol
A ______ hydronic system is a hydronic system in which circulation to the heating units is accomplished by the difference in the density of water in the supply and return mains. A) Mechanical B) gravity C) steam D) closed
Gravity
Periodically, a hydronic system may require additional water because of loss of ___. a. pressure b. saturated air c. latent heat d. HTF
HTF
_________ Law states that the amount of air that can be dissolved in water at a given pressure depends inversely on the temperature and directly on the pressure of the water at a given temperature. a. Henry's b. Newton's c. Graham's d. Faraday's
Henry's
A (n) _____ flow meter is a flow meter that measures the displacement of a tapered piston or float. a. incline b. circuit sensor c. variable-temperature d. electronic
Inline
The aluminum layer in _____ limits oxygen diffusion through the walls of the tubing. a. PP b. EVOH c. PEX-AL-PEX d. PEX
PEX-AL-PEX
____ has low density compared to other thermoplastics and a unique combination of properties including mechanical strength and thermal stability. a. Polyvinyl chloride (PVC) b. Cross- linked polyethylene (PEX) c. Chlorinated polyvinyl chloride (CPVC) d. Polypropylene (PP)
Polypropylene (PP)
_____ has a maximum service temperature of 140F. a. Chlorinated polyvinyl chloride (CPVC) b. Polyvinyl chloride (PVC) c. cross-linked polyethylene (PEX) d. Polypropylene (PP)
Polyvinyl chloride (PVC)
______-valve is the measure if thermal resistance of a material or product. a. R b. T c. M d. P
R
A ____ is a device that allows for instant visual balancing of hot or cold water flows. a. Circuit setter balancing valve b. flanged circuit setter Plus balancing valve c. ThermoFLo balanacer d. Triple Duty valve
ThermoFlo balancer
From the point of view of the controller, ______ are output devices. a. human-machine interfaces b. sensors c. actuators d. control signals
actuators
Hydronic system equipment that is normally installed in a mechanical room includes ___________ a. valves and other regulating devices used to isolate or control the flow of HTF b. a condensate pan, trap, and drain c. a chiller or other method to create chilled HTF d. terminal units to transfer heat between the HTF and the building space
a chiller or other method to create chilled HTF
Of the types of chilled beams, _______systems are similar to convection systems and have ventilation are delivered through ductwork by a central air-handling system. a. passive b. multiple-beam c. active d. single-beam
active
A ____________ thermometer is an instrument designed to measure temperature using a circular scale and pointer. a. liquid-in-glass b. infrared c. dial d. thermistor
dial
_____ signals are commonly used to an output to turn devices on and off, typically through relays that switch the power needed to operate the device. a. hardware-based b. digital c. software-based d. analog
digital
Most technicians today use a(n) ______ to test for voltage, current, and resistance. a. analog ammeter b. analog multimeter c. digital multimeter d. digital ammeter
digital multimeter
A ______ is a fitting that creates a greater-than-normal pressure drop in a line in order to divert flow to another line. a. three-elbow swing b. coupling c. supply riser d. diversion fitting
diversion fitting
In a four-pipe system, a _____ valve is generally recommended when high differential pressures are encountered. a. single-seated two-way b. double-seated two-way c. single-seated one-way d. double-seated one-way
double-seated two-way
Which boiler has the highest output rating? a. cast iron b. scotch marine c. condensing d. electric
electric
_______ problems can be caused by faulty or deteriorating line power wiring. a. electrical b. equipment c. component d. HTF flow
electrical
A condenser acts as a type of _________? a. compressor b. cooling tower c. heat exchanger d. balancing fitting
heat exchanger
What is the device that can be used to both heat and cool an area? a. heat pump b. chiller c. boiler d. cooling tower
heat pump
In the early 1900s, closed hydronic systems were still gravity-based systems that relied on the __________ in the system to circulate the water and were slow to affect temperature change in the building. A) high pressures and temperatures B) high pressures and low temperatures C) low pressures and high temperatures D)low pressures and temperatures
high pressure and temperatures
When determining the best location for air separators, the point of _______ should receive first consideration. a. highest temperature b. lowest temperature c. lowest pressure d. highest pressure
highest temperature
________ forces or pressures occur when a fluid is not moving but is at rest. a. hygrometic b. hydrostatic c. psychrometric d. dynamic
hydrostatic
____ is the controlled and forced phase change of snow and/or ice to liquid and vapor with effluent drained away from a surface in a safe manner. a. snow and ice melting b. frost melting c. frost management d. snow and ice management
snow and ice melting
_____ systems are used on driveways, walkways, parking areas, stairways, ramps, loading docks, and other outside surfaces. a. radiant floor panel b. snow melt c. radiant ceiling panel d. radiant wall panel
snow melt
_____ are typically used in quick-acting valves and for locking and unlocking doors. a. solenoids b. electric motors c. control signals d. relays
solenoids
______ pressure is the pressure caused by the height of water above any given point. a. dynamic b. operating c. pump d. static
static
______ is the vertical distance liquid is raised by the atmospheric pressure from the surface of a supply reservoir to the centerline of the pump suction connection. a. static discharge head b. total discharge lift c. static suction lift d. total static head
static suction lift
______ pipe is normally used for larger sized hydronic heating and cooling piping in commercial and industrial installations. a. copper b. zinc c. steel d. plastic
steel
The ____ prevents damage to a steam pressure gauge by forming a water seal to keep steam from entering the gauge. a. gauge cock b. needle valve c. straight coil siphon d. cylinder cock
straight coil siphon
When vapor is heated to a temperature higher than is boiling point, it is said to be _________. a. superheated b. saturated c. fused d. steamed
superheated
Heat transfer is the flow of heat from one object or substance to another, and it occurs because of a difference in__________. a. speed b. pressure c. volume d. temperature
temperature
