Chapter 5: Temperature and Heat
TRUE/FALSE
1. Heat is transferred from a substance if it is exposed to something that has a lower
temperature.
2. A barometer can work because of a bimetallic strip.
3. One “food calorie” equals 1000 calories.
4. A thermostat can work because of a bimetallic strip.
5. A bimetallic strip is formed from two materials that have different heat capacities.
6. Celsius degrees are larger than Fahrenheit degrees.
7. A hot pizza contains heat.
8. On the Kelvin scale the temperature is proportional to the average kinetic energy of the
atoms or molecules whose temperature is being measured.
9. When you hold one end of a solid rod in a fire, the other end becomes hot because of heat
convection.
10. You feel warm from the sun at the beach because of heat radiation.
11. A wood stove in the corner of a cabin causes the entire cabin to become heated because of
heat conduction.
12. A bimetallic strip is usable in a thermometer because of its heat capacity.
13. A refrigerator is an example of a heat mover.
14. As the air cools at night the relative humidity usually drops.
15. A steam turbine is an example of a heat mover.
16. You can increase the internal energy of a gas by heating it or by compressing it.
17. Natural processes tend to increase the entropy of thermodynamic systems.
18. The coefficient of linear expansion of ordinary glass is three times that of Pyrex glass. An
ordinary glass rod and a Pyrex glass rod of equal lengths at room temperature are dropped
into boiling water. The change in length of the ordinary glass rod will be 3 times the change
in length of the Pyrex glass rod.
19. The specific heat capacity of copper is three times the specific heat capacity of lead. Equal
masses of copper and lead are heated from room temperature to the temperature of boiling
water. To achieve this, the amount of heat added to the copper is 3 times the amount of heat
added to the lead.
20. When ice melts, its temperature increases.
21. When you add heat to ice, its temperature always stays constant.
22. When water boils, its temperature increases.
23. Water is good for putting out fires because it has a very high latent heat of vaporization.
24. The specific heat capacity of water is about twice the specific heat capacity of ice. The
amount of heat required to boil 1 kg of water is twice the amount of heat required to melt 1
kg of ice.
25. The latent heat of vaporization of water is roughly 10 times the latent heat of fusion of
water. The amount of heat required to boil away 1 kg of water is 10 times the amount of
heat required to melt 1 kg of ice.
26. You can increase the temperature of a gas by compressing it.
27. A liquid cannot be heated simultaneously by conduction, convection, and radiation.
28. A 1 kg block of ice is removed from a freezer where its temperature was –10°C. The amount
of heat absorbed by the ice as it warms to 0°C is 20,000 J.
29. The 1 kg block of ice melts into water. The amount of heat absorbed by the ice as it melts is
334,000 J.
30. As the ice is melting, the temperature of the ice-water mixture rises by 10°C.
31. After the 1 kg block of ice melts, the amount of heat required to raise its temperature to
10°C is 3,340,000 J.
32. The Eiffel tower in Paris is made primarily of iron, whose coefficient of linear expansion is
about 10 10-6/°C. On a cold day when the temperature is -10°C the Eiffel tower is 300
meters tall. Its height on a hot day when the temperature is 40°C is 300.15 m.
33. At 96°F the saturation density of air is 0.04 kg/m3. If the weather report says the relative
humidity is 90% when the temperature is 96°F, the humidity is 0.036 kg/m3.
34. Air at a temperature of 32°F has a relative humidity of 60%. If the temperature of the same
air increases, the relative humidity increases.
35. In a steam engine, steam at 140°C in a turbine does work on an external system, and the
steam leaves the turbine at 100°C. The efficiency of the steam engine is 5%. The relevant
physical principle is the first law of thermodynamics.
36. A piston compresses a gas, while at the same time heat is lost to the surroundings. The
temperature of the gas rises. This is governed by the second law of thermodynamics.
37. Temperature is a measure of heat.
38. Evaporation is when a gas is converted into a liquid.
39. The dew point is the temperature at which a given humidity equals the saturation density.
40. Internal energy can only be changed by adding heat
MULTIPLE CHOICE
1. When a substance is exposed to something that has a lower temperature,
a.
work is done on it
b.
work is done by it
c.
heat is transferred from it
d.
heat is transferred to it
e.
none of the above
2. Which is larger, a calorie or a joule?
a.
calorie
b.
joule
c.
Neither—they are the same.
d.
They cannot be compared since they measure different physical quantities.
3. One “food calorie” equals
a.
1 calorie
c.
1000 calories
b.
100 calories
d.
none of the above
4. A device that makes use of a bimetallic strip is a
a.
thermometer
b.
thermostat
c.
choke control in an old automobile
d.
all of the above
e.
none of the above
5. A bimetallic strip is formed from two materials that have different
a.
coefficients of linear expansion
b.
heat capacities
c.
calories
d.
phase transitions
e.
relative humidities
6. A key is placed in a hot oven and warmed to 100°C. As a result
a.
the hole in the key becomes smaller
b.
the key is bent into an arc
c.
the key becomes longer
d.
all of the above
7. The temperature scale where the numerical value is proportional to the average kinetic
energy of the atoms or molecules is
a.
Fahrenheit
c.
Kelvin
b.
Celsius
d.
none of the above
8. Which are bigger—Celsius degrees or Fahrenheit degrees?
a.
Fahrenheit
b.
Celsius
c.
Neither—they are the same size.
d.
This is a nonsensical comparison.
9. Which of these is stated properly?
a.
“The temperature of liquid nitrogen is 77 Kelvin.”
b.
“The temperature of liquid nitrogen is 77 Kelvins.”
c.
“The temperature of liquid nitrogen is 77 degrees Kelvin.”
d.
“The temperature of liquid nitrogen is 77 Kelvin degrees.”
10. Temperature measures
a.
how much heat is in a substance
b.
the internal energy of an object
c.
the average speed of atoms and molecules in a substance
d.
the average kinetic energy of atoms and molecules in a substance
11. In a gas of different types of molecules all at the same temperature, the speeds of the heavier
molecules will generally be _____________ the speeds of the lighter molecules.
a.
the same as
c.
less than
b.
greater than
d.
unrelated to
12. You hold one end of a solid rod in a fire, and the other end becomes hot. This is an example
of
a.
heat conduction
b.
heat convection
c.
heat radiation
d.
thermal expansion
e.
none of the above
13. The warmth you feel from the sun at the beach is an example of
a.
heat conduction
b.
heat convection
c.
heat radiation
d.
thermal expansion
e.
none of the above
14. A wood stove in the corner of a cabin causes the entire cabin to become heated. This is an
example of
a.
heat conduction
b.
heat convection
c.
heat radiation
d.
thermal expansion
e.
none of the above
15. A piece of chocolate melts in your mouth. This is an example of
a.
heat conduction
b.
heat convection
c.
heat radiation
d.
thermal expansion
e.
none of the above
16. The lunar surface cools after the sun sets. This is an example of
a.
heat conduction
b.
heat convection
c.
heat radiation
d.
thermal expansion
e.
none of the above
17. “Firewalkers” step on the hot ashes and coals from a wood fire without getting their feet
burned. How might this be possible?
a.
They have magical powers.
b.
The ashes are poor conductors of heat.
c.
They do get burned but enjoy the publicity.
d.
none of the above
18. A bimetallic strip is usable as a thermometer because of
a.
heat conduction
b.
heat convection
c.
heat radiation
d.
thermal expansion
e.
none of the above
19. An example of a heat mover is a(n)
a.
refrigerator
b.
air conditioner
c.
heat pump
d.
all of the above
e.
none of the above
20. The amount of heat energy a refrigerator removes from the food stored inside it is
___________ the amount of electrical energy required to run the refrigerator.
a.
equal to
c.
less than
b.
greater than
d.
unrelated to
21. A hot pizza contains
a.
heat
b.
internal energy
c.
temperature
d.
work
e.
none of the above
22. The total kinetic and potential energies of all the atoms and molecules of a substance is its
a.
heat
b.
internal energy
c.
temperature
d.
thermodynamics
e.
none of the above
23. The change in size of an object due to thermal expansion depends upon
a.
what the object is made of
b.
the object’s original size
c.
how much the temperature changes
d.
A and C
e.
all of the above
24. The coefficient of linear expansion of ordinary glass is three times that of Pyrex glass. An
ordinary glass rod and a Pyrex glass rod of equal lengths at room temperature are dropped
into boiling water. The change in length of the ordinary glass rod will be ___________ the
change in length of the Pyrex glass rod.
a.
1/9
b.
1/3
c.
equal to
d.
3 times
e.
9 times
25. The specific heat capacity of copper is three times the specific heat capacity of lead. Equal
masses of copper and lead are heated from room temperature to the temperature of boiling
water. To achieve this, the amount of heat added to the copper is ___________ the amount
of heat added to the lead.
a.
1/9
b.
1/3
c.
equal to
d.
3 times
e.
9 times
26. When ice melts, its temperature
a.
increases
c.
stays constant
b.
decreases
d.
cannot be determined
27. When water boils, its temperature
a.
increases
c.
stays constant
b.
decreases
d.
cannot be determined
28. When droplets of condensation form on the outside of a glass of ice water, it must be that in
the air right next to the glass
a.
the temperature is near the dew point
b.
the humidity is near the saturation density
c.
the relative humidity is near 100%
d.
all of the above
29. Natural processes tend to increase the __________ of thermodynamic systems.
a.
temperature
c.
Carnot efficiency
b.
internal energy
d.
entropy
30. What’s wrong with the statement “heat rises?”
a.
Nothing—heat does rise.
b.
One should say “energy rises.”
c.
One should say “heated air (or other fluid) rises.”
d.
none of the above
31. The specific heat capacity of water is about twice the specific heat capacity of ice. From this
information, the amount of heat required to boil 1 kg of water is ________ the amount of
heat required to melt 1 kg of ice.
a.
1/2
c.
2 times
b.
equal to
d.
unrelated to
32. The latent heat of vaporization of water is roughly 10 times the latent heat of fusion of
water. The amount of heat required to boil away 1 kg of water is __________ the amount of
heat required to melt 1 kg of ice.
a.
one tenth
b.
equal to
c.
10 times
d.
unrelated to
33. The temperature of a gas can be increased by
a.
compressing it
b.
adding heat to it
c.
doing work on it
d.
all of the above
e.
none of the above
34. Which mechanism(s) of heat transfer will work in a vacuum?
a.
conduction
c.
radiation
b.
convection
d.
none of the above
35. A 1 kg block of ice is removed from a freezer where its temperature was –10°C. The amount
of heat absorbed by the ice as it warms to 0°C is
a.
2,000 J
b.
4,000 J
c.
20,000 J
d.
40,000 J
e.
334,000 J
36. The 1 kg block of ice melts into water. The amount of heat absorbed by the ice as it melts is
a.
2,000 J
b.
4,000 J
c.
20,000 J
d.
40,000 J
e.
334,000 J
37. As the ice is melting, the temperature of the ice-water mixture rises by
a.
0°C
b.
+5°C
c.
–5°C
d.
+10°C
e.
–10°C
38. After the 1 kg block of ice melts, the amount of heat required to raise its temperature to 10
°C is
a.
2,000 J
b.
4,000 J
c.
20,000 J
d.
40,000 J
e.
334,000 J
39. The Eiffel tower in Paris is made primarily of iron, whose coefficient of linear expansion is
about 10 10-6/°C. On a cold day when the temperature is –10°C the Eiffel tower is 300
meters tall. Its height on a hot day when the temperature is 40°C is
a.
300.0015 m
b.
300.015 m
c.
300.15 m
d.
301.5 m
e.
315 m
40. Why do bridges have expansion joints?
a.
They would buckle and crack otherwise.
b.
to let water run off
c.
to absorb vibrations due to traffic
d.
for ease in construction
41. At 96° F the saturation density of air is 0.04 kg/m3. If the weather report says the relative
humidity is 90 % when the temperature is 96°F, the humidity is
a.
10 %
b.
0.9
c.
0.004 kg/m3