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Halliday/Resnick/Walker
Fundamentals of Physics
Classroom Response System Questions
Chapter 18 Temperature, Heat, and the First Law of
Thermodynamics
Interactive Lecture Questions
18.3.1. Which one of the following situations is described by the zeroth law of
thermodynamics?
a) An air conditioner transfers heat from the inside of a house to the outside of the house.
b) A monatomic gas is held within a container that has a moveable piston. The gas
absorbs heat from the surroundings and expands at constant pressure and
temperature.
c) A container with adiabatic walls holds boiling water. A thermometer is calibrated by
inserting it into the boiling water and allowing it to reach thermal equilibrium with
the water.
d) A pot contains oil at 175 C. When frozen sliced potatoes are dropped into the oil,
heat is transferred from the oil to the potatoes.
e) A physicist removes energy from a system in her laboratory until it reaches a
temperature of 3  1010 K, a temperature very close to (but still greater than)
absolute zero.
18.3.1. Which one of the following situations is described by the zeroth law of
thermodynamics?
a) An air conditioner transfers heat from the inside of a house to the outside of the house.
b) A monatomic gas is held within a container that has a moveable piston. The gas
absorbs heat from the surroundings and expands at constant pressure and
temperature.
c) A container with adiabatic walls holds boiling water. A thermometer is calibrated by
inserting it into the boiling water and allowing it to reach thermal equilibrium with
the water.
d) A pot contains oil at 175 C. When frozen sliced potatoes are dropped into the oil,
heat is transferred from the oil to the potatoes.
e) A physicist removes energy from a system in her laboratory until it reaches a
temperature of 3  1010 K, a temperature very close to (but still greater than)
absolute zero.
18.4.1. Which one of the following properties is not likely to be used
as a temperature-sensitive property to construct a thermometer?
a) The volume of a liquid increases with increasing temperature.
b) A gas held within a constant volume container exhibits pressure
changes with corresponding temperature changes.
c) The length of a metal rod changes linearly with temperature.
d) The mass of a solid decreases with increasing temperature.
e) The electrical resistance of a wire increases with increasing
temperature.
18.4.1. Which one of the following properties is not likely to be used
as a temperature-sensitive property to construct a thermometer?
a) The volume of a liquid increases with increasing temperature.
b) A gas held within a constant volume container exhibits pressure
changes with corresponding temperature changes.
c) The length of a metal rod changes linearly with temperature.
d) The mass of a solid decreases with increasing temperature.
e) The electrical resistance of a wire increases with increasing
temperature.
18.5.1. Unsatisfied with the Celsius and Kelvin temperature scales,
you decide to create your own. On your temperature scale, the ice
point is 0.0 M and the steam point is at 366.1 M, where “M”
stands for “my scale.” What temperature on your scale
corresponds to 0 K?
a) 273.1 M
b) 500.0 M
c) 1000.0 M
d) 732.4 M
e) 633.9 M
18.5.1. Unsatisfied with the Celsius and Kelvin temperature scales,
you decide to create your own. On your temperature scale, the ice
point is 0.0 M and the steam point is at 366.1 M, where “M”
stands for “my scale.” What temperature on your scale
corresponds to 0 K?
a) 273.1 M
b) 500.0 M
c) 1000.0 M
d) 732.4 M
e) 633.9 M
18.5.2. Three thermometers are used to measure the temperature inside a closed,
insulated box. Thermometer A is calibrated in Fahrenheit degrees, thermometer
B in Celsius degrees, and thermometer C in kelvins. When the thermometers
reach thermal equilibrium with the interior of the box, B reads 40 C and C
reads 233 K. Which one of the following statements is necessarily true?
a) Thermometer C should read 233 K.
b) Thermometer A must read –40 °F.
c) If the temperature of the interior of the box is increased until A reads 20 F,
thermometer B will read 10 C.
d) Thermometer B should read 77 C.
e) If the temperature of the interior of the box is increased until C reads 293 K,
thermometer A will read 36 F.
18.5.2. Three thermometers are used to measure the temperature inside a closed,
insulated box. Thermometer A is calibrated in Fahrenheit degrees, thermometer
B in Celsius degrees, and thermometer C in kelvins. When the thermometers
reach thermal equilibrium with the interior of the box, B reads 40 C and C
reads 233 K. Which one of the following statements is necessarily true?
a) Thermometer C should read 233 K.
b) Thermometer A must read –40 °F.
c) If the temperature of the interior of the box is increased until A reads 20 F,
thermometer B will read 10 C.
d) Thermometer B should read 77 C.
e) If the temperature of the interior of the box is increased until C reads 293 K,
thermometer A will read 36 F.
18.6.1. An artist wishes to insert a gold pin into a hole in an iron sculpture and have it
held permanently. The pin is slightly larger than the hole. The coefficient of linear
thermal expansion of gold is slightly larger than that of iron. Consider the following
options: (1) increase the temperature of the pin and the sculpture by the same
amount, (2) decrease the temperature of the pin and the sculpture by the same
amount, (3) increase the temperature of the pin and decrease the temperature of the
sculpture, and (4) decrease the temperature of the pin and increase the temperature
of the sculpture. Which of the choices would most likely accomplish the artist’s
task?
a) 1
b) 2
c) 3
d) 4
e) 2 and 4
18.6.1. An artist wishes to insert a gold pin into a hole in an iron sculpture and have it
held permanently. The pin is slightly larger than the hole. The coefficient of linear
thermal expansion of gold is slightly larger than that of iron. Consider the following
options: (1) increase the temperature of the pin and the sculpture by the same
amount, (2) decrease the temperature of the pin and the sculpture by the same
amount, (3) increase the temperature of the pin and decrease the temperature of the
sculpture, and (4) decrease the temperature of the pin and increase the temperature
of the sculpture. Which of the choices would most likely accomplish the artist’s
task?
a) 1
b) 2
c) 3
d) 4
e) 2 and 4
18.6.2. The length of an aluminum pendulum in a certain clock is 0.2480 m
on a day when the temperature is 23.30 C. This length was chosen so
that the period of the pendulum is exactly 1.000 s. The clock is then
hung on a wall where the temperature is 5.00 C and set to the correct
local time. Assuming the acceleration due to gravity is the same at both
locations, by how much time is the clock incorrect after one day at this
temperature?
a) 69.3 s
b) 115 s
c) 87.2 s
d) 31.0 s
e) 11.5 s
18.6.2. The length of an aluminum pendulum in a certain clock is 0.2480 m
on a day when the temperature is 23.30 C. This length was chosen so
that the period of the pendulum is exactly 1.000 s. The clock is then
hung on a wall where the temperature is 5.00 C and set to the correct
local time. Assuming the acceleration due to gravity is the same at both
locations, by how much time is the clock incorrect after one day at this
temperature?
a) 69.3 s
b) 115 s
c) 87.2 s
d) 31.0 s
e) 11.5 s
18.6.3. A rod of length L is heated so that its temperature increases by
T. As a result, the length of the rod increases by L. The rod is
then cut into two pieces, one of length L/3 and one of length 2L/3.
What is the ratio of the change in length of the rod of length 2L/3
to L of the original rod when its temperature is increased by T?
a) 1/3
b) 2/3
c) 1
d) 3/2
e) 3
18.6.3. A rod of length L is heated so that its temperature increases by
T. As a result, the length of the rod increases by L. The rod is
then cut into two pieces, one of length L/3 and one of length 2L/3.
What is the ratio of the change in length of the rod of length 2L/3
to L of the original rod when its temperature is increased by T?
a) 1/3
b) 2/3
c) 1
d) 3/2
e) 3
18.6.4. Which one of the following statements is the best explanation for the
fact that metal pipes that carry water often burst during cold winter
months?
a) Both the metal and the water expand, but the water expands to a greater
extent.
b) Water contracts upon freezing while the metal expands at lower
temperatures.
c) The metal contracts to a greater extent than the water.
d) The interior of the pipe contracts less than the outside of the pipe.
e) Water expands upon freezing while the metal contracts at lower
temperatures.
18.6.4. Which one of the following statements is the best explanation for the
fact that metal pipes that carry water often burst during cold winter
months?
a) Both the metal and the water expand, but the water expands to a greater
extent.
b) Water contracts upon freezing while the metal expands at lower
temperatures.
c) The metal contracts to a greater extent than the water.
d) The interior of the pipe contracts less than the outside of the pipe.
e) Water expands upon freezing while the metal contracts at lower
temperatures.
18.6.5. Consider the four blocks made from the same material that are
shown in the drawing. The sides have lengths of L, 2L, or 3L.
Rank these blocks according to their expected increase, largest to
smallest, in their volumes when their temperatures are increased
by the same amount.
a) B > C > A > D
b) C > B > A > D
c) D > C > A > B
d) C > D > B > A
e) All would have the same increase in volume.
18.6.5. Consider the four blocks made from the same material that are
shown in the drawing. The sides have lengths of L, 2L, or 3L.
Rank these blocks according to their expected increase, largest to
smallest, in their volumes when their temperatures are increased
by the same amount.
a) B > C > A > D
b) C > B > A > D
c) D > C > A > B
d) C > D > B > A
e) All would have the same increase in volume.
18.6.6. A square piece of metal has a hole drilled through its center. If
the metal piece is uniformly heated, what is the effect on the hole?
a) The diameter of the hole will decrease, but remain open, as the
temperature increases.
b) The diameter of the hole will increase as the temperature increases.
c) The diameter of the hole will not change, but the area of the square
will increase as the temperature increases.
d) The diameter of the hole may either increase or decrease depending
on the type of metal.
18.6.6. A square piece of metal has a hole drilled through its center. If
the metal piece is uniformly heated, what is the effect on the hole?
a) The diameter of the hole will decrease, but remain open, as the
temperature increases.
b) The diameter of the hole will increase as the temperature increases.
c) The diameter of the hole will not change, but the area of the square
will increase as the temperature increases.
d) The diameter of the hole may either increase or decrease depending
on the type of metal.
18.7.1. Why is water often used as a coolant in automobiles, other than
the fact that it is abundant?
a) Water expands very little as it is heated.
b) The freezing temperature of water has a relatively large value.
c) The specific heat of water is relatively small and its temperature
can be rapidly decreased.
d) The specific heat of water is relatively large and it can store a great
deal of thermal energy.
e) Water does not easily change into a gas.
18.7.1. Why is water often used as a coolant in automobiles, other than
the fact that it is abundant?
a) Water expands very little as it is heated.
b) The freezing temperature of water has a relatively large value.
c) The specific heat of water is relatively small and its temperature
can be rapidly decreased.
d) The specific heat of water is relatively large and it can store a great
deal of thermal energy.
e) Water does not easily change into a gas.
18.8.1. A certain amount of heat Q is added to materials A, B, and C. The
masses of these three materials are 0.04 kg, 0.01 kg, and 0.02 kg,
respectively. The temperature of material A increases by 4.0 C while
the temperature of the other two materials increases by only 3.0 C.
Rank these three materials from the largest specific heat capacity to
the smallest value.
a) A > B > C
b) C > B > A
c) B > A > C
d) B = C > A
e) A > B = C
18.8.1. A certain amount of heat Q is added to materials A, B, and C. The
masses of these three materials are 0.04 kg, 0.01 kg, and 0.02 kg,
respectively. The temperature of material A increases by 4.0 C while
the temperature of the other two materials increases by only 3.0 C.
Rank these three materials from the largest specific heat capacity to
the smallest value.
a) A > B > C
b) C > B > A
c) B > A > C
d) B = C > A
e) A > B = C
18.8.2. A swimming pool has a width of 9.0 m and a length of 12.0 m.
The depth of the water is 1.83 m. One morning, the temperature of
the pool water was 15.0 C. The water then absorbed 2.00  109 J
of heat from the Sun. What is the final temperature of the water?
Assume no heat loss to the surroundings.
a) 16.9 C
b) 18.1 C
c) 17.4 C
d) 19.6 C
e) 20.2 C
18.8.2. A swimming pool has a width of 9.0 m and a length of 12.0 m.
The depth of the water is 1.83 m. One morning, the temperature of
the pool water was 15.0 C. The water then absorbed 2.00  109 J
of heat from the Sun. What is the final temperature of the water?
Assume no heat loss to the surroundings.
a) 16.9 C
b) 18.1 C
c) 17.4 C
d) 19.6 C
e) 20.2 C
18.8.3. Which of the following substances would be the most effective
in cooling 0.300 kg of water at 98 C?
a) 0.100 kg of lead at 22 C
b) 0.100 kg of water at 22 C
c) 0.100 kg of glass at 22 C
d) 0.100 kg of aluminum at 22 C
e) 0.100 kg of copper at 22 C
18.8.3. Which of the following substances would be the most effective
in cooling 0.300 kg of water at 98 C?
a) 0.100 kg of lead at 22 C
b) 0.100 kg of water at 22 C
c) 0.100 kg of glass at 22 C
d) 0.100 kg of aluminum at 22 C
e) 0.100 kg of copper at 22 C
18.8.4. Britanny’s normal body temperature is 36.5 C. When she
recently became ill, her body temperature increased to 38.0 C.
What was the minimum amount of heat required for this increase
in body temperature if her weight is 561 N?
a) 2.96  106 J
b) 3.50  103 J
c) 4.98  104 J
d) 3.00  105 J
e) 7.60  105 J
18.8.4. Britanny’s normal body temperature is 36.5 C. When she
recently became ill, her body temperature increased to 38.0 C.
What was the minimum amount of heat required for this increase
in body temperature if her weight is 561 N?
a) 2.96  106 J
b) 3.50  103 J
c) 4.98  104 J
d) 3.00  105 J
e) 7.60  105 J
18.8.5. Four 1-kg cylinders are heated to 100 C and placed on top of a
block of paraffin wax, which melts at 63 C. There is one cylinder
made from lead, one of copper, one of aluminum, and one of iron.
After a few minutes, it is observed that the cylinders have sunk into
the paraffin to differing depths. Rank the depths of the cylinders
from deepest to shallowest.
a) lead > iron > copper > aluminum
b) aluminum > copper > lead > iron
c) aluminum > iron > copper > lead
d) copper > aluminum > iron > lead
e) iron > copper > lead > aluminum
18.8.5. Four 1-kg cylinders are heated to 100 C and placed on top of a
block of paraffin wax, which melts at 63 C. There is one cylinder
made from lead, one of copper, one of aluminum, and one of iron.
After a few minutes, it is observed that the cylinders have sunk into
the paraffin to differing depths. Rank the depths of the cylinders
from deepest to shallowest.
a) lead > iron > copper > aluminum
b) aluminum > copper > lead > iron
c) aluminum > iron > copper > lead
d) copper > aluminum > iron > lead
e) iron > copper > lead > aluminum
18.8.6. Heat is added to a substance, but its temperature does not
increase. Which one of the following statements provides the best
explanation for this observation?
a) The substance has unusual thermal properties.
b) The substance must be cooler than its environment.
c) The substance must be a gas.
d) The substance must be an imperfect solid.
e) The substance undergoes a change of phase.
18.8.6. Heat is added to a substance, but its temperature does not
increase. Which one of the following statements provides the best
explanation for this observation?
a) The substance has unusual thermal properties.
b) The substance must be cooler than its environment.
c) The substance must be a gas.
d) The substance must be an imperfect solid.
e) The substance undergoes a change of phase.
18.8.7. What is the final temperature when 2.50  105 J are added to
0.950 kg of ice at 0.0 C?
a) 0.0 C
b) 4.2 C
c) 15.7 C
d) 36.3 C
e) 62.8 C
18.8.7. What is the final temperature when 2.50  105 J are added to
0.950 kg of ice at 0.0 C?
a) 0.0 C
b) 4.2 C
c) 15.7 C
d) 36.3 C
e) 62.8 C
18.8.8. By adding 25 kJ to solid material A, 4.0 kg will melt. By
adding 50 kJ to solid material B, 6.0 kg will melt. Solid material C
requires 30 kJ to melt 3.0 kg. Which of these materials, if any, has
the largest value for the heat of fusion?
a) A
b) B
c) C
d) A = B
18.8.8. By adding 25 kJ to solid material A, 4.0 kg will melt. By
adding 50 kJ to solid material B, 6.0 kg will melt. Solid material C
requires 30 kJ to melt 3.0 kg. Which of these materials, if any, has
the largest value for the heat of fusion?
a) A
b) B
c) C
d) A = B
18.8.9. Consider the system shown in the drawing. A test tube containing water is
inserted into boiling water. Will the water in the test tube eventually boil?
a) Yes, heat is continually transferred to the water
inside the test tube and eventually it will boil?
b) Yes, the pressure above the water in the test tube
will be reduced to less than atmospheric pressure
and cause the water to boil.
c) No, heat will only be transferred until the water
in the test tube is 100 C.
d) No, the temperature of the water in the test tube will never reach 100 C.
18.8.9. Consider the system shown in the drawing. A test tube containing water is
inserted into boiling water. Will the water in the test tube eventually boil?
a) Yes, heat is continually transferred to the water
inside the test tube and eventually it will boil?
b) Yes, the pressure above the water in the test tube
will be reduced to less than atmospheric pressure
and cause the water to boil.
c) No, heat will only be transferred until the water
in the test tube is 100 C.
d) No, the temperature of the water in the test tube will never reach 100 C.
18.10.1. An insulated container is filled with a mixture of water and
ice at zero C. An electric heating element inside the container is
used to add 1680 J of heat to the system while a paddle does 450 J
of work by stirring. What is the increase in the internal energy of
the ice-water system?
a) 450 J
b) 1230 J
c) 1680 J
d) 2130 J
e) zero J
18.10.1. An insulated container is filled with a mixture of water and
ice at zero C. An electric heating element inside the container is
used to add 1680 J of heat to the system while a paddle does 450 J
of work by stirring. What is the increase in the internal energy of
the ice-water system?
a) 450 J
b) 1230 J
c) 1680 J
d) 2130 J
e) zero J
18.10.2. The internal energy of a system increases during some time interval.
Which one of the following statements concerning this situation must be
true?
a) The increase in internal energy indicates that work was done on the system.
b) The increase in internal energy indicates that heat was added to the system.
c) The increase in internal energy indicates that work was done by the system.
d) The increase in internal energy indicates that heat was removed from the
system.
e) The information given is insufficient to indicate the reason for the increase.
18.10.2. The internal energy of a system increases during some time interval.
Which one of the following statements concerning this situation must be
true?
a) The increase in internal energy indicates that work was done on the system.
b) The increase in internal energy indicates that heat was added to the system.
c) The increase in internal energy indicates that work was done by the system.
d) The increase in internal energy indicates that heat was removed from the
system.
e) The information given is insufficient to indicate the reason for the increase.
18.10.3. A gas is enclosed in a cylinder by a piston. The volume of the gas is
then reduced to one half its original value by applying a force to the
piston. Which one of the following statements concerning the internal
energy of the gas is true?
a) The internal energy of the gas will decrease.
b) The internal energy of the gas will increase.
c) The internal energy of the gas will neither increase nor decrease.
d) The internal energy of the gas will equal the work done in moving the
piston.
e) The internal energy of the gas may increase, decrease, or remain the same
depending on the amount of heat that is gained or lost by the gas.
18.10.3. A gas is enclosed in a cylinder by a piston. The volume of the gas is
then reduced to one half its original value by applying a force to the
piston. Which one of the following statements concerning the internal
energy of the gas is true?
a) The internal energy of the gas will decrease.
b) The internal energy of the gas will increase.
c) The internal energy of the gas will neither increase nor decrease.
d) The internal energy of the gas will equal the work done in moving the
piston.
e) The internal energy of the gas may increase, decrease, or remain the same
depending on the amount of heat that is gained or lost by the gas.
18.10.4. Which one of the following statements is not consistent with the
first law of thermodynamics?
a) The internal energy of a finite system must be finite.
b) An engine may be constructed such that the work done by the machine
exceeds the energy input to the engine.
c) An isolated system that is thermally insulated cannot do work on its
surroundings nor can work be done on the system.
d) The internal energy of a system decreases when it does work on its
surroundings and there is no flow of heat.
e) An engine may be constructed that gains energy while heat is transferred
to it and work is done on it.
18.10.4. Which one of the following statements is not consistent with the
first law of thermodynamics?
a) The internal energy of a finite system must be finite.
b) An engine may be constructed such that the work done by the machine
exceeds the energy input to the engine.
c) An isolated system that is thermally insulated cannot do work on its
surroundings nor can work be done on the system.
d) The internal energy of a system decreases when it does work on its
surroundings and there is no flow of heat.
e) An engine may be constructed that gains energy while heat is transferred
to it and work is done on it.
18.11.1. Consider the pressure-versus-volume plot shown. There are
eight points labeled and the choices below indicate possible multistep processes. In which one of the processes does the work done
have the largest value?
a) GHBD
b) GFBD
c) HABD
d) EDFH
e) CBFG
18.11.1. Consider the pressure-versus-volume plot shown. There are
eight points labeled and the choices below indicate possible multistep processes. In which one of the processes does the work done
have the largest value?
a) GHBD
b) GFBD
c) HABD
d) EDFH
e) CBFG
18.11.2. Consider the pressure-versus-volume plot shown. There are eight
points labeled and the choices below indicate possible multi-step
processes. If the initial state of the system is at A and the final state is at
E, which of the following paths between these two states results in the
largest increase in internal energy of the system?
a) AHDE
b) ABFE
c) AGE
d) ACE
e) All paths between A and E are equivalent.
18.11.2. Consider the pressure-versus-volume plot shown. There are eight
points labeled and the choices below indicate possible multi-step
processes. If the initial state of the system is at A and the final state is at
E, which of the following paths between these two states results in the
largest increase in internal energy of the system?
a) AHDE
b) ABFE
c) AGE
d) ACE
e) All paths between A and E are equivalent.
18.11.3. An insulated container with rigid walls has two compartments
within. One compartment contains n moles of an ideal gas and the other
compartment has been evacuated. A valve connecting the two chambers
is opened at time t = 0 s. Which one of the following statements
concerning this situation is true?
a) There is no change in the internal energy of the gas.
b) There is no change in the pressure of the gas.
c) The temperature of the gas decreases with time.
d) Work is done by the gas as it fills the previously evacuated compartment.
e) The gas will remain in the first compartment unless heat is added to the
system.
18.11.3. An insulated container with rigid walls has two compartments
within. One compartment contains n moles of an ideal gas and the other
compartment has been evacuated. A valve connecting the two chambers
is opened at time t = 0 s. Which one of the following statements
concerning this situation is true?
a) There is no change in the internal energy of the gas.
b) There is no change in the pressure of the gas.
c) The temperature of the gas decreases with time.
d) Work is done by the gas as it fills the previously evacuated compartment.
e) The gas will remain in the first compartment unless heat is added to the
system.
18.12.1. During the summer, sunlight warms the land beside a cool lake. This
warming is followed by a breeze blowing from the direction of the lake toward
the land. Which of the following provides the best explanation for this summer
breeze?
a) Air naturally flows from cooler locations to warmer locations.
b) The lake must be west of the land because winds typically blow from the west.
c) The land is usually cooler near a lake, so this is a case of temperature inversion
which causes air to blow from the direction of the lake.
d) Warm air rises above the land and cooler air moves downward, appearing to
come from the direction of the lake, but it is really from above the land.
e) Warm air rises from above the land and is replaced by the air blowing in from the
lake.
18.12.1. During the summer, sunlight warms the land beside a cool lake. This
warming is followed by a breeze blowing from the direction of the lake toward
the land. Which of the following provides the best explanation for this summer
breeze?
a) Air naturally flows from cooler locations to warmer locations.
b) The lake must be west of the land because winds typically blow from the west.
c) The land is usually cooler near a lake, so this is a case of temperature inversion
which causes air to blow from the direction of the lake.
d) Warm air rises above the land and cooler air moves downward, appearing to
come from the direction of the lake, but it is really from above the land.
e) Warm air rises from above the land and is replaced by the air blowing in from the
lake.
18.12.2. Randy has placed 10 thermometers at different depths and radii within a pot of
water on an electric stove. He then turns on the heating element under the pot and
watches the thermometers. He notices that the temperature of the water at the ten
locations is approximately the same as the temperature increases from room
temperature to 100 C. Which one of the flowing statements best describes the
nearly uniform temperature throughout the pot?
a) Convection currents appear that evenly distribute heat throughout the pot.
b) Heat is rapidly conducted from the bottom of the pot to the top because of the
temperature gradient that exists between the bottom of the pot and the top.
c) The pressure at a given depth in the water must remain constant.
d) The water is heated via radiation. The bottom of the pot is hotter than the water and
all water molecules are irradiated equally.
e) The water molecules near the bottom receive energy from the pot and transfer that
energy as they collide with other water molecules throughout the pot.
18.12.2. Randy has placed 10 thermometers at different depths and radii within a pot of
water on an electric stove. He then turns on the heating element under the pot and
watches the thermometers. He notices that the temperature of the water at the ten
locations is approximately the same as the temperature increases from room
temperature to 100 C. Which one of the flowing statements best describes the
nearly uniform temperature throughout the pot?
a) Convection currents appear that evenly distribute heat throughout the pot.
b) Heat is rapidly conducted from the bottom of the pot to the top because of the
temperature gradient that exists between the bottom of the pot and the top.
c) The pressure at a given depth in the water must remain constant.
d) The water is heated via radiation. The bottom of the pot is hotter than the water and
all water molecules are irradiated equally.
e) The water molecules near the bottom receive energy from the pot and transfer that
energy as they collide with other water molecules throughout the pot.
18.12.3. A candle is burning at the bottom of a vertical tube. A second
vertical tube is inserted in the tube just above the candle as shown.
What will happen if the second tube is removed?
a) The flame will go out.
b) The flame will burn less brightly.
c) The flame will continue to burn
the same as before.
d) The flame will burn more brightly.
18.12.3. A candle is burning at the bottom of a vertical tube. A second
vertical tube is inserted in the tube just above the candle as shown.
What will happen if the second tube is removed?
a) The flame will go out.
b) The flame will burn less brightly.
c) The flame will continue to burn
the same as before.
d) The flame will burn more brightly.
18.12.4. Consider the following substances all at room temperature:
(1) aluminum, (2) copper, (3) steel, and (4) wood. Which one
would feel the coolest if held in your hand (which is at a
temperature above room temperature)?
a) 1
b) 2
c) 3
d) 4
e) All would feel the same temperature.
18.12.4. Consider the following substances all at room temperature:
(1) aluminum, (2) copper, (3) steel, and (4) wood. Which one
would feel the coolest if held in your hand (which is at a
temperature above room temperature)?
a) 1
b) 2
c) 3
d) 4
e) All would feel the same temperature.
18.12.5. A wall is composed of four different materials as shown in the
drawing. The wall on the right is maintained at 30.0 C and the other
wall is at 0.5 C. The temperatures at the interfaces between the
various materials are given. Rank the materials in order of largest
thermal conductivity to smallest thermal conductivity.
a) A > B > C > D
b) B > C > D > A
c) C > D > A > B
d) D > A > C > B
e) C > B > A > D
18.12.5. A wall is composed of four different materials as shown in the
drawing. The wall on the right is maintained at 30.0 C and the other
wall is at 0.5 C. The temperatures at the interfaces between the
various materials are given. Rank the materials in order of largest
thermal conductivity to smallest thermal conductivity.
a) A > B > C > D
b) B > C > D > A
c) C > D > A > B
d) D > A > C > B
e) C > B > A > D
18.12.6. Two bars are placed between two plates: one at temperature THOT and one
at TCOLD. The thermal conductivity of bar A is three times that of bar B. The
cross-sectional area of bar A is one-half that of bar B. There is no heat loss from
the sides of the bars. Which one of the following statements correctly describes
the heat conducted by the two bars in a time interval t?
a) The amount of heat conducted by bar A
is 3 times that conducted by bar B.
b) The amount of heat conducted by bar A
is 3/2 times that conducted by bar B.
c) The amount of heat conducted by bar A is the same as that conducted by bar B.
d) The amount of heat conducted by bar A is 2/3 times that conducted by bar B.
e) The amount of heat conducted by bar A is 1/3 times that conducted by bar B.
18.12.6. Two bars are placed between two plates: one at temperature THOT and one
at TCOLD. The thermal conductivity of bar A is three times that of bar B. The
cross-sectional area of bar A is one-half that of bar B. There is no heat loss from
the sides of the bars. Which one of the following statements correctly describes
the heat conducted by the two bars in a time interval t?
a) The amount of heat conducted by bar A
is 3 times that conducted by bar B.
b) The amount of heat conducted by bar A
is 3/2 times that conducted by bar B.
c) The amount of heat conducted by bar A is the same as that conducted by bar B.
d) The amount of heat conducted by bar A is 2/3 times that conducted by bar B.
e) The amount of heat conducted by bar A is 1/3 times that conducted by bar B.
18.12.7. What thickness of concrete, with a thermal conductivity of
1.1 W/(mK) will conduct heat at the same rate as 0.25 m of air,
which has a thermal conductivity of 0.0256 W/(mK), if all other
conditions are the same?
a) 8.9 m
b) 4.3 m
c) 1.4 m
d) 11 m
e) 0.25 m
18.12.7. What thickness of concrete, with a thermal conductivity of
1.1 W/(mK) will conduct heat at the same rate as 0.25 m of air,
which has a thermal conductivity of 0.0256 W/(mK), if all other
conditions are the same?
a) 8.9 m
b) 4.3 m
c) 1.4 m
d) 11 m
e) 0.25 m
18.12.8. Just before spring arrives, an airplane flies over some mountains and drops black soot
on the snow and ice. This procedure is done to prevent flooding of the valley below
when the warmer weather arrives with spring. How does this procedure prevent
flooding?
a) The areas where the soot fails should melt earlier than those without the soot as sunlight
will be absorbed. Melting the snow gradually reduces the amount that will melt as
temperatures rise in spring.
b) The soot increases the temperature at which snow and ice melt causing the areas that have
soot to melt later.
c) The soot lowers the temperature at which snow and ice melt causing the areas that have
soot to melt earlier.
d) The soot has a higher thermal conductivity than water and ice and can transmit heat from
the air more efficiently to the snow and ice underneath the soot.
e) Air convection warms the soot covered snow more efficiently than the snow without soot.
18.12.8. Just before spring arrives, an airplane flies over some mountains and drops black soot
on the snow and ice. This procedure is done to prevent flooding of the valley below
when the warmer weather arrives with spring. How does this procedure prevent
flooding?
a) The areas where the soot fails should melt earlier than those without the soot as sunlight
will be absorbed. Melting the snow gradually reduces the amount that will melt as
temperatures rise in spring.
b) The soot increases the temperature at which snow and ice melt causing the areas that have
soot to melt later.
c) The soot lowers the temperature at which snow and ice melt causing the areas that have
soot to melt earlier.
d) The soot has a higher thermal conductivity than water and ice and can transmit heat from
the air more efficiently to the snow and ice underneath the soot.
e) Air convection warms the soot covered snow more efficiently than the snow without soot.
18.12.9. Metal pots used in cooking on top of a stove are usually very shiny
on the top and sides. Which one of the following choices indicates why
this is a good idea thermally?
a) The shiny parts of the pot have greater thermal conductivity.
b) The shiny parts of the pot have greatly reduced losses via convection.
c) The shiny parts of the pot have greatly reduced losses via radiation.
d) The shiny parts of the pot have greatly reduced losses via conduction.
e) The shiny parts of the pot do not allow any heat to be lost to the
environment.
18.12.9. Metal pots used in cooking on top of a stove are usually very shiny
on the top and sides. Which one of the following choices indicates why
this is a good idea thermally?
a) The shiny parts of the pot have greater thermal conductivity.
b) The shiny parts of the pot have greatly reduced losses via convection.
c) The shiny parts of the pot have greatly reduced losses via radiation.
d) The shiny parts of the pot have greatly reduced losses via conduction.
e) The shiny parts of the pot do not allow any heat to be lost to the
environment.
18.12.10. A device that is to be primarily used in the desert is being designed.
The user would like the side facing the sun, the front, to absorb as little heat
as possible and to lose as little heat on the opposite side, the back, of the
device. Two materials for these sides of the device are being recommended:
(1) a dull black material and (2) a shiny, metallic material. Which of these
materials should be used for the front and back sides of the device?
a) The front should be material 2 and the back should be material 1.
b) The front should be material 1 and the back should be material 2.
c) Both sides should be material 1.
d) Both sides should be material 2.
e) Using either of these materials for the front and back will have the same
result.
18.12.10. A device that is to be primarily used in the desert is being designed.
The user would like the side facing the sun, the front, to absorb as little heat
as possible and to lose as little heat on the opposite side, the back, of the
device. Two materials for these sides of the device are being recommended:
(1) a dull black material and (2) a shiny, metallic material. Which of these
materials should be used for the front and back sides of the device?
a) The front should be material 2 and the back should be material 1.
b) The front should be material 1 and the back should be material 2.
c) Both sides should be material 1.
d) Both sides should be material 2.
e) Using either of these materials for the front and back will have the same
result.
18.12.11. Two sealed containers are initially at the same temperature
and have the same dimensions. The outer surfaces of container A
appear to be polished aluminum. The outer surfaces of container B
are roughened gray cast iron. A large, bright incandescent light
bulb is brought near both containers and shines on them for equal
amounts of time from the same distance. Within which container,
if either, will the temperature increase at the fastest rate?
a) A
b) B
c) The temperature of both containers will increase at the same rate.
18.12.11. Two sealed containers are initially at the same temperature
and have the same dimensions. The outer surfaces of container A
appear to be polished aluminum. The outer surfaces of container B
are roughened gray cast iron. A large, bright incandescent light
bulb is brought near both containers and shines on them for equal
amounts of time from the same distance. Within which container,
if either, will the temperature increase at the fastest rate?
a) A
b) B
c) The temperature of both containers will increase at the same rate.