WorksheetsUnit 1 Quiz
Total questions: 92
Worksheet time: 49mins
What is the term "heat" defined as?
The device used to measure temperature
A state of matter
Energy that causes molecules to be in motion and to raise the temperature of a substance
A unit of temperature measurement
What term is used to describe the level of heat or molecular activity, expressed in Fahrenheit, Rankine, Celsius, or Kelvin units?
Heat
Temperature
Pressure
Energy
Why are accurate temperature readings important in the HVAC/R industry?
They are required for system documentation
They determine the color of the heating system
They influence decisions regarding system operation
They are only important for educational purposes
What type of thermometer is shown in Figure 1.1?
Liquid-in-glass thermometer
Infrared thermometer
Bimetallic strip thermometer
Thermocouple thermometer
What is the term used to describe the weight of the atmosphere's gases pressing down on the Earth?
Atmospheric weight
Atmospheric density
Atmospheric pressure
Atmospheric mass
At what value is atmospheric pressure equal at sea level and 70°F?
14.696 psi
15.000 psi
13.500 psi
12.960 psi
What equipment is used to measure the system operating pressures in air-conditioning and refrigeration equipment?
Thermometer
Barometer
Refrigeration gauge manifold
Anemometer
What is the importance of knowing system operating pressures and various temperature readings in HVAC/R systems?
They are useful for weather forecasting.
They provide valuable information to properly evaluate and troubleshoot heating and cooling equipment.
They are only necessary for installing new equipment.
They are used to measure the efficiency of electrical appliances.
Temperature can be thought of as a description of the level of heat and is also known as what?
Heat content
Heat intensity
Molecular motion
Heat capacity
What is the boiling point of water at standard atmospheric conditions?
32°F
203°F
212°F
167°F
At what temperature does water freeze at standard atmospheric conditions?
32°F
203°F
212°F
167°F
According to the text, what happens to the molecular motion of a substance when it receives more heat?
It decreases
It remains the same
It increases
It changes state
What is the boiling point of water in Denver, Colorado, which is about 5,600 feet above sea level?
32°F
203°F
212°F
167°F
What instrument is used to measure temperature?
Barometer
Thermometer
Hygrometer
Anemometer
What is the lowest attainable temperature called, at which molecular motion stops and there is no heat present?
Boiling point
Melting point
Absolute zero
Room temperature
What is the theoretical temperature known as absolute zero in Fahrenheit?
32°F
0°F
-273°F
-460°F
Which temperature scale is part of the English measurement system used in the United States?
Kelvin
Celsius
Fahrenheit
Rankine
What temperature scale is part of the International System of Units (SI)?
Kelvin
Celsius
Fahrenheit
Rankine
At what temperature does pure water boil at sea level according to the Fahrenheit scale?
100°F
212°F
350°F
32°F
What is the equivalent temperature of the average human body temperature in Celsius?
0°C
37°C
100°C
177°C
What is the formula to convert Celsius temperature to Fahrenheit temperature?
°F = (1.8 × °C) + 32
°F = (2.0 × °C) + 30
°F = (°C ÷ 1.8) + 32
°F = (°C - 32) ÷ 1.8
What is the formula to convert Fahrenheit temperature to Celsius temperature?
°C = (°F - 32) ÷ 1.8
°C = (°F ÷ 1.8) - 32
°C = (°F + 32) ÷ 1.8
°C = (°F × 1.8) - 32
What is the Fahrenheit equivalent of 20°C?
68°F
50°F
72°F
80°F
What is the Celsius equivalent of 50°F?
10°C
0°C
20°C
15°C
What is the name of the absolute temperature scale in Fahrenheit?
Celsius scale
Kelvin scale
Rankine scale
Newton scale
What is the name of the absolute temperature scale in Celsius?
Celsius scale
Kelvin scale
Rankine scale
Newton scale
At what point do all molecular motion stops on the Rankine scale?
0° Rankine
32° Rankine
100° Rankine
212° Rankine
At what point do all molecular motion stops on the Kelvin scale?
0 Kelvin
273 Kelvin
100 Kelvin
373 Kelvin
At what temperature does water boil according to the Fahrenheit scale?
212°F
100°C
373 K
672°R
At what temperature does water freeze according to the Celsius scale?
32°F
0°C
273 K
492°R
What is the equivalent of absolute zero in Celsius?
0°C
-273°C
-460°F
0 K
Which of the following thermometer types uses the Rankine scale?
What does the first law of thermodynamics state?
Energy can be created and destroyed.
Energy can be neither created nor destroyed, but can be converted from one form to another.
Energy is continuously created from heat.
Energy is only transferred from one substance to another.
What is the British thermal unit (Btu) used to describe?
The amount of heat required to raise the temperature of 1 pound of water by 1°F.
The amount of heat a substance contains at absolute zero.
The rate of heat transfer in an air-conditioning system.
The temperature difference required for heat transfer to occur.
What is the capacity of an air-conditioning system that is rated at 24,000 Btu/h?
It can convert 24,000 Btu of energy from gas to oil every hour.
It can transfer 24,000 Btu of heat energy to the structure every hour.
It can remove 24,000 Btu of heat energy from the structure every hour.
It can create 24,000 Btu of energy every hour.
What is temperature a measure of?
The quantity of heat or heat content in a substance.
The rate of heat transfer in an air-conditioning system.
The amount of molecular motion in a substance at absolute zero.
The level of heat with reference to absolute zero.
What happens when a temperature difference exists between two substances?
Heat transfer does not occur.
Heat is created in the warmer substance.
Heat transfer occurs, moving from a warmer to a cooler substance.
The cooler substance makes the warmer substance cold.
What does the example in the image illustrate about the quantity of heat in relation to the size of the water tanks?
A) A larger tank of water will cool to room temperature faster because it contains more heat.
B) A smaller tank of water will cool to room temperature faster because it contains less heat.
C) Both tanks will cool at the same rate because they are heated to the same temperature.
D) The temperature of the water is not related to the quantity of heat in the tanks.
Why will the 10-lb tank of water cool to room temperature faster than the 100,000-lb tank, even though both are heated to 200°F?
A) Because the 10-lb tank has a higher temperature.
B) Because the 100,000-lb tank has a lower heat intensity level.
C) Because the 10-lb tank contains a smaller quantity of heat.
D) Because the 100,000-lb tank is exposed to a higher flame.
What is the purpose of comparing a 10-lb tank of water heated to 200°F with a 100,000-lb tank of water heated to the same temperature?
To show that larger quantities of water require more heat to reach the same temperature
To illustrate that the depth of water in feet is a measure of water quantity
To demonstrate that heat intensity level and quantity of heat are different concepts
To prove that a 200-ft-deep well contains as much water as a large lake
What does the depth of water in feet tell us according to the text?
The temperature of the water
The level of water, but not the quantity in gallons
The heat intensity level of the water
The exact quantity of water in gallons
Why is the term "cold" considered a level of heat absence?
Because cold is a numerical value representing temperature
Because cold is a positive value in relation to heat
Because cold is used to express a relationship to the normal expected temperature for the time of year or to the inside temperature
Because cold is a measure of the quantity of heat
What is the rating of a furnace that is needed to heat a house on the coldest day?
10,000-Btu/h
25,000-Btu/h
75,000-Btu/h
100,000-Btu/h
Which material is mentioned as one of the best conductors of electricity and heat?
Wood
Glass
Copper
Plastic
What is glass considered to be in terms of conducting electricity and heat?
A good conductor
The best conductor
One of the poorest conductors
A moderate conductor
According to the text, substances that are poor conductors of heat are usually also poor conductors of what else?
Light
Sound
Electricity
Magnetism
What is natural convection?
Heat transfer from one place to another using a solid.
Heat transfer from one place to another using a fluid.
Heat transfer from one place to another without any movement.
Heat transfer from one place to another using radiation.
What happens to air when it is heated according to the principle of natural convection?
It becomes more dense and sinks.
It becomes less dense and rises.
It remains at the same density and moves horizontally.
It condenses and forms water droplets.
What is the temperature of the supply air to the structure as shown in the diagram?
70°F
130°F
100°F
90°F
What is the temperature of the return air from the room as shown in the diagram?
70°F
130°F
100°F
90°F
Which component of the system is responsible for heating the air?
Blower
Flue
Heat exchanger
Gas flame for heat
What occurs during natural convection as illustrated in Figure 1.11?
Cold air rises and hot air takes its place.
Hot air rises and cold air takes its place.
Hot air is pushed out by mechanical means.
Cold air is heated by a mechanical device.
According to the detail in Figure 1.11, why does warm air rise?
Because it is cooler and denser than the surrounding air.
Because it is being forced out by a fan.
Because it is now lighter as it expands.
Because it is being pulled by a vacuum.
Heat transfer by radiation is unique because it:
Requires a medium like air or water to transfer heat
Can only travel through a vacuum such as space
Is not dependent on matter as a medium of heat transfer
Increases in intensity by the square of the distance traveled
According to the inverse-square law, if you double the distance from a light bulb, the heat intensity you feel will:
Double
Remain the same
Decrease by a factor of 2
Decrease by a factor of 4
What does radiant heat not transfer?
Light
The actual temperature
Heat quantity over a distance
Radiant energy
When you move your hand from 1 foot to 2 feet away from a light bulb, the amount of heat you feel is:
The same as at 1 foot
Twice the amount at 1 foot
Half the amount at 1 foot
One-fourth the amount at 1 foot
What is sensible heat?
Heat that cannot be measured with a thermometer
Heat that causes a change in temperature
Heat that does not cause a change in temperature
Heat that can only be felt but not measured
What is latent or hidden heat?
Heat energy that causes a change in temperature
Heat energy absorbed or rejected when a substance is changing state and there is no change in temperature
Heat energy that is visible during a chemical reaction
Heat energy that is lost to the environment
What happens when heat is added to water while it is boiling in an open container?
The temperature of the water decreases
The water boils faster without a rise in temperature
The water immediately freezes
The temperature of the water increases
What is the latent heat of vaporization for water at atmospheric conditions?
970 Btu/lb
970.3 Btu/lb
1000 Btu/lb
212 Btu/lb
How much heat energy is required to change 1 lb of water at 212°F to 1 lb of steam at the same temperature?
970 Btu
970.3 Btu
1000 Btu
212 Btu
What is the latent heat of condensation?
The heat given off when a solid changes to a liquid
The heat absorbed when a liquid changes to a gas
The heat given off when refrigerant condenses
The heat absorbed when a gas changes to a solid
What is the latent heat of fusion?
The amount of heat energy required to change the state of a substance from a gas to a liquid
The amount of heat energy required to change the state of a substance from a liquid to a solid or from a solid to a liquid
The amount of heat energy lost when a substance decomposes
The amount of heat energy gained when a substance melts at a constant temperature
What is the amount of heat energy, in Btu/lb, required to change 1 lb of steam at 212°F to 1 lb of water at the same temperature?
970 Btu
144 Btu
180 Btu
16 Btu
How much heat energy is needed to melt 1 lb of ice at 32°F?
970 Btu
144 Btu
180 Btu
16 Btu
What is the latent heat of fusion for water at atmospheric conditions?
970 Btu/lb
144 Btu/lb
180 Btu/lb
16 Btu/lb
If you have 1 lb of water at 32°F and you want to freeze it, how much heat energy must be removed?
970 Btu
144 Btu
180 Btu
16 Btu
What does an increase in latent heat cause in water?
A decrease in temperature
A change of state
No change in properties
A decrease in volume
According to Figure 1.14, what is the total heat content in Btu for 1 lb of water at the boiling point?
970 Btu
144 Btu
180 Btu
1310 Btu
How much heat energy is required to raise the temperature of 1 lb of ice from 0°F to 32°F?
0.5 Btu
16 Btu
144 Btu
180 Btu
What happens when 144 Btu of heat is added to 1 lb of ice at 32°F?
The ice temperature rises above 32°F.
The ice melts to 1 lb of water without a temperature change.
The ice remains at 32°F without melting.
The ice cools below 32°F.
What is the result of adding 180 Btu of heat energy to 1 lb of water at 32°F?
The water freezes into ice.
The water temperature rises to 212°F.
The water remains at 32°F.
The water evaporates into steam.
What is the term used to describe the vapor temperature above the boiling point?
Condensing
Sensible heat
Superheating
Latent heat
How much heat energy is required to heat 1 lb of water vapor (steam) 1°F in the vapor state?
0.5 Btu
16 Btu
144 Btu
970 Btu
What is the definition of specific heat according to the text?
The amount of heat required to change the state of 1 lb of a substance
The amount of heat required to raise the temperature of 1 lb of a substance 1°F
The temperature change when 1 Btu of heat is added to 1 lb of water
The difference in temperature when a substance is heated or cooled
How much does the temperature of water rise when 1 Btu of heat is added to 1 lb of it?
0.5°F
1°F
2°F
It does not change
What is the specific heat of water as shown in the specific heat table?
0.24 Btu/lb°F
0.50 Btu/lb°F
0.92 Btu/lb°F
1.00 Btu/lb°F
Which of the following substances has a specific heat that is less than that of water according to the specific heat table?
Aluminum
Ice
Steel
All of the above
Why is specific heat significant when sizing heating equipment?
It determines the color of the equipment.
It affects the amount of heat required to change the temperatures of different substances.
It is used to calculate the weight of the equipment.
It indicates the durability of the heating equipment.
What is the desired metal temperature for machining in the example provided?
0°F
70°F
1000 lb/h
8120 Btu/h
What is the specific heat of steel given in the example for calculating the quantity of heat needed?
1000 lb/h
8120 Btu/h
0.116 Btu/lb/°F
70°F
How much heat is required to heat the steel for machining according to the example?
0.116 Btu
70 Btu
1000 Btu
8120 Btu/h
What formula is used to calculate the quantity of heat needed in the example?
Q = Weight × Specific Heat × Temperature Difference
Q = Weight / Specific Heat × Temperature Difference
Q = Weight + Specific Heat + Temperature Difference
Q = Weight - Specific Heat - Temperature Difference
How is pressure defined according to the text?
Pressure is defined as the amount of force exerted on a surface.
Pressure is defined as force per unit of volume.
Pressure is defined as force per unit of area.
Pressure is defined as the weight of an object divided by the area it covers.
What is the pressure exerted by a 1-lb weight resting on an area of 1 square inch?
100 psi
1 psi
0.433 psi
62.4 psi
If a 100-lb weight rests on a 1-square-inch surface, what is the pressure exerted?
1 psi
100 psi
0.433 psi
62.4 psi
Why do you feel pressure when swimming under the surface of the water?
Because there is less pressure high in the air than down on the ground.
Because the weight of the water pushes down on you.
Because the pressure is greater inside your body and is pushing out.
Because the water's temperature increases the pressure.
What is the pressure at the bottom of a cube that weighs 62.4 lb/ft³ and has a bottom area of 144 in²?
1 psi
100 psi
0.433 psi
62.4 psi
How much pressure does one cubic foot of water exert downward on the bottom surface area of a cube?
0.108 psi
62.4 lb/ft²
1728 psi
7.48 gal
If the same volume of water is in a container with a base of 24 inches by 24 inches, what would be the resulting pressure at the bottom?
0.108 psi
62.4 lb/ft²
1728 psi
576 lb/ft²
What is the purpose of wearing snowshoes while walking across the snow?
To increase the pressure on the snow
To look fashionable
To reduce the chance of sinking into the snow
To keep the feet warm
