College Physics - Final Exam

When a vapor condenses A) the temperature of the substance decreases. B) heat energy leaves the substance. C) the temperature of the substance increases. D) heat energy enters the substance.

B) heat energy leaves the substance.

The heat required to change a substance from the solid to the liquid state is referred to as the A) heat of melting. B) heat of fusion. C) heat of vaporization. D) heat of freezing. E) heat of condensation.

B) heat of fusion.

The process shown on the p-V graph in Fig. 12-5 is an A) isometric expansion. B) isobaric expansion. C) adiabatic expansion. D) isothermal expansion.

B) isobaric expansion.

) A substance is taken through the illustrated cycle in Fig. 12-3 from (p1,v1) to (3p1,2v1) to (p1,2v1) back to (p1,v1). How much work was done? A) 5p1v1 B) p1v1 C) 3p1v1 D) 4p1v1 E) 2p1v1

B) p1v1

An ideal gas is compressed isothermally from 30 L to 20 L. During this process, 6 J of energy is expended by the external mechanism that compressed the gas. What is the change of internal energy for this gas? A) -12 J B) zero C) +12 J D) +6 J E) -6 J

B) zero

When the first law of thermodynamics, Q = Δu + W, is applied to an ideal gas that is taken through an isothermal process, A) W = 0. B) Δu = 0. C) Q = 0. D) ΔP = 0.

B) Δu = 0.

A gas is allowed to expand at constant pressure as heat is added to it. This process is A) isobaric. B) adiabatic. C) isometric. D) isothermal. E) isentropic.

A) isobaric.

The statement that ʺheat energy cannot be completely transformed into workʺ is a statement of which thermodynamic law? A) third B) fourth C) second D) first E) zeroth

C) second

Only Carnot efficiency is A) 1 - Tcold/Thot. B) 1 - Thot/Tcold. C) Qout/Win. D) 1 - Qhot/Qcold. E) 1 - Qcold/Qhot

A) 1 - Tcold/Thot.

Object 1 has three times the specific heat capacity and four times the mass of Object 2. The two objects are given the same amount of heat. If the temperature of Object 1 changes by an amount ΔT, the change in temperature of Object 2 will be A) 12ΔT. B) 6ΔT. C) 3/4 ΔT. D) 4/3 ΔT. E) ΔT.

A) 12ΔT

During a strenuous period of extravehicular activity, an astronaut generates 2.0 MJ of heat per hour, which must be removed by means of the liquid cooling and ventilating garment (LCVG) worn under the spacesuit. How much water must be circulated in the LCVG to remove this quantity of heat if it takes it from the astronaut at 37 °C and dumps it at 0°C? A) 13 kg/hr B) 7.8 kg/hr C) 26 kg/hr D) 1.5 kg/hr E) 480 kg/hr

A) 13 kg/hr

) Betelgeuse is a star in the constellation Orion. It radiates heat at the rate of 3.00 × 1030 W and has a surface temperature of 3000 K. Assuming that it is a perfect emitter, what is the radius of Betelgeuse? The Stefan-Boltzmann constant is 5.67 × 10-8 W/(m2∙K4). A) 2.30 × 1011 m B) 1.40 × 1011 m C) 1.90 × 1011 m D) 7.80 × 1010 m E) 8.70 × 1010 m

A) 2.30 × 1011 m

A certain gas is compressed adiabatically. The amount of work done on the gas is 800 J. What is the change in the internal energy of the gas? A) 800 J B) 0 J C) 400 J D) -800 J E) More information is needed to answer this question.

A) 800 J

For an ideal monatomic gas, A) Cp > Cv. B) Cp = Cv. C) Cp < Cv. D) More information is needed to answer this question.

A) Cp > Cv.

A pendulum clock has a pendulum shaft made of aluminum which has a coefficient of linear expansion of 24.0 × 10-6 K-1. At 22°C the period of swing of the pendulum is 1.00 s. If the temperature is reduced to 5°C, how much time does the clock gain or lose in one day? A) It gains 18 s per day. B) It loses 18 s per day. C) It loses 9.0 s per day. D) It gains 9.0 s per day. E) It neither gains nor loses time.

A) It gains 18 s per day.

Coefficient of performance is A) Q/m. B) 1 - Qcold/Qhot. C) Q - W. D) Qout/Win. E) 1 - Tcold/Thot.

A) Q/m.

A fixed container holds oxygen and helium gases at the same temperature. Which of the following statements are correct? (There could be more than one correct choice.) A) The helium molecules have the same average kinetic as the oxygen molecules. B) The oxygen molecules have the greater speed. C) The oxygen molecules have the greater average kinetic energy. D) The helium molecules have the greater speed. E) The helium molecules have the greater average kinetic energy.

A) The helium molecules have the same average kinetic as the oxygen molecules. D) The helium molecules have the greater speed.

Phase changes occur A) as the temperature remains the same. B) as the temperature decreases. C) as the temperature increases. D) all of the above E) none of the above

A) as the temperature remains the same.

When water freezes, the entropy of the water A) decreases. B) could either increase or decrease; it depends on other factors. C) does not change. D) increases.

A) decreases.

The second law of thermodynamics leads us to conclude that A) disorder in the universe is increasing with the passage of time. B) the total energy of the universe is constant. C) it is theoretically possible to convert heat into work with 100% efficiency. D) the average temperature of the universe is increasing with the passage of time

A) disorder in the universe is increasing with the passage of time.

A liquid boils when its vapor pressure A) equals the external pressure. B) exceeds the external pressure. C) equals the equilibrium vapor pressure. D) is between the equilibrium vapor pressure and the external pressure. E) None of the other choices is correct.

A) equals the external pressure.

When a solid melts A) heat energy enters the substance. B) heat energy leaves the substance. C) the temperature of the substance decreases. D) the temperature of the substance increases.

A) heat energy enters the substance

The heat required to change a substance from the liquid to the vapor state is referred to as the A) heat of vaporization. B) heat of fusion. C) heat of evaporation. D) heat of condensation. E) heat of melting.

A) heat of vaporization.

The work done by the gas is zero during an A) isometric process. B) isobaric expansion. C) adiabatic expansion. D) isothermal expansion.

A) isometric process.

The type of heat transfer that occurs between a heating lamp and the food that it is keeping warm is A) radiative. B) countercurrent. C) convective. D) conductive. E) evaporation.

A) radiative.

The change in entropy is Q/T for A) reversible processes. B) all real engines. C) irreversible processes. D) all processes. E) exothermic processes.

A) reversible processes.

When a bimetallic strip is heated, the strip will bend toward the side A) with the smaller coefficient of linear expansion. B) with the lower temperature. C) with the larger coefficient of linear expansion. D) with the higher temperature.

A) with the smaller coefficient of linear expansion.

If the absolute temperature of an object is tripled, the thermal power radiated per unit surface area of this object will (assuming that its emissivity is not affected by the temperature change) A) increase by a factor of 81. B) increase by a factor of 27. C) increase by a factor of 18. D) increase by a factor of 9. E) increase by a factor of 3.

A)increase by a factor of 81

Being the ideal engine, the maximum COP of a Carnot cycle operated in reverse as a refrigerator is A) 100. B) (Tc/Th) ∙ (1 - Tc/Th)-1. C) (1 - Tc/Th)-1. D) (Th/Tc)(1 - Tc/Th)-1.

B) (Tc/Th) ∙ (1 - Tc/Th)-1.

An irreversible engine operating between the temperatures of 550 K and 300 K extracts 1200 J of heat from the hot reservoir and produces 450 J of work. How much entropy is created in the process? A) 0.73 J/K B) 0.32 J/K C) 0.68 J/K D) 0 J/K E) 0.44 J/K

B) 0.32 J/K

A Carnot engine operates between two reservoirs with unknown temperatures. If the Carnot engine operates at 67% efficiency, what is the ratio of the absolute temperatures of the reservoirs, Tc/Th? A) 0.0025 B) 0.33 C) 0.0012 D) 0.67

B) 0.33

An object having a fixed emissivity of 0.725 radiates heat at a rate of 10 W when it is at an absolute temperature T. If its temperature is doubled to 2T, at what rate will it now radiate? A) 20 W B) 160 W C) 40 W D) 80 W E) 320 W

B) 160 W

Platinum melts at 3215°F. What is the corresponding temperature in the Kelvin scale? A) 3215 K B) 2041 K C) 2207 K D) 2296 K E) 2135 K

B) 2041 K

An ideal monatomic gas undergoes the reversible expansion shown in Figure 18-1, where V2 = 5 V1 and P2 = 3P1. What is the change in internal energy of the gas in this process, in terms of the initial pressure and volume? A) 7P1V1 B) 21P1V1 C) 29P1V1 D) 15P1V1 E) 14P1V1

B) 21P1V1

A refrigerator has an interior volume of 0.500 m3. The temperature inside the refrigerator in 282 K, and the pressure is 101 kPa. If the molecular weight of air is 29 g/mol, what is the mass of air inside the refrigerator? A) 243 g B) 625 g C) 513 g D) 447 g E) 329 g

B) 625 g

An example of a reversible process is the A) Swinn cycle. B) Carnot cycle. C) Joule cycle. D) Otto cycle. E) Wenkle cycle.

B) Carnot cycle.

A monatomic ideal gas is cooled to one-half its original temperature during an isometric process. The final pressure of the gas A) increases to twice its original value. B) decreases to half its original value. C) increases to more than twice its original value. D) does not change.

B) decreases to half its original value.

A thermally isolated system is made up of a hot piece of aluminum and a cold piece of copper; the aluminum and the copper are in thermal contact. The specific heat capacity of aluminum is more than double that of copper. Which object experiences the greater magnitude gain or loss of heat during the time the system takes to reach thermal equilibrium? A) the copper B) the aluminum C) neither; both experience the same size gain or loss of heat D) it is impossible to tell without knowing the masses E) it is impossible to tell without knowing the volumes

C) neither; both experience the same size gain or loss of heat

A gas is taken through the cycle shown in the pV diagram in the figure. During one cycle, how much work is done by the gas? A) 4 p0V0 B) p0V0 C) 3 p0V0 D) 2 p0V0

C) 3 p0V0

What is the root mean square value of the following velocity components: 2.0 m/s, -3.0 m/s, and 4.0 m/s? A) 3.3 m/s B) 1.0 m/s C) 3.1 m/s D) 1.9 m/s E) 5.4 m/s

C) 3.1 m/s

The ocean thermal energy conversion project uses the surface water near tropical islands with a temperature of 20.0°C as the hot temperature reservoir, and the water at some depth, with a temperature of 5.0°C, as the cold temperature reservoir for a heat engine. What is the maximum efficiency of an engine running between those two temperatures? A) 7.9% B) 15% C) 5.1% D) 4.7% E) 30%

C) 5.1%

The molecular weight of nitrogen is 28 g/mol. What is the rms speed of nitrogen molecules at 8.0°C? A) 550 m/s B) 600 m/s C) 500 m/s D) 450 m/s E) 650 m/s

C) 500 m/s

The compressor in a certain Carnot refrigerator performs 480 J of work to remove 150 J of heat from the interior of the refrigerator. How much heat must the coils behind the refrigerator discharge into the kitchen? A) 110 J B) 150 J C) 630 J D) 330 J E) 480 J

C) 630 J

An ideal Carnot heat engine has an efficiency of 0.600. If it operates between a deep lake with a constant temperature of 294.0 K and a hot reservoir, what is the temperature of the hot reservoir? A) 490 K B) 470 K C) 735 K D) 784 K

C) 735 K

The most efficient engine possible is the A) Otto cycle. B) Kelvin cycle. C) Carnot cycle. D) Joule cycle. E) Wright cycle.

C) Carnot cycle.

If the efficiency of a Carnot engine were to be 100%, the heat sink would have to be A) infinitely hot. B) at 100°C. C) at absolute zero. D) at 0°C.

C) at absolute zero.

As a system loses its ability to do useful work A) energy decreases. B) energy increases. C) entropy increases. D) entropy remains constant. E) entropy decreases.

C) entropy increases.

When a liquid evaporates A) heat energy leaves the substance. B) the temperature of the substance decreases. C) heat energy enters the substance. D) the temperature of the substance increases.

C) heat energy enters the substance.

When a liquid freezes A) the temperature of the substance decreases. B) the temperature of the substance increases. C) heat energy leaves the substance. D) heat energy enters the substance.

C) heat energy leaves the substance.

The process shown on the T-V graph in Fig. 12-7 is an A) isobaric compression. B) isometric compression. C) isothermal compression. D) adiabatic compression.

C) isothermal compression.

When the first law of thermodynamics, Q = Δu + W, is applied to an ideal gas that is taken through an isobaric process, A) Δu = 0. B) Q = 0. C) it is not true that Δu = 0 or W = 0 or Q = 0. D) W = 0.

C) it is not true that Δu = 0 or W = 0 or Q = 0.

When a gas expands adiabatically, A) heat flows out of the system. B) the internal energy of the gas increases. C) the internal energy of the gas decreases. D) there is no work done by the gas. E) work is done on the gas.

C) the internal energy of the gas decreases.

A monatomic ideal gas is compressed isothermically to one-third of its initial volume. The resulting pressure will be A) less than three times as large as the initial value. B) equal to the initial value. C) three times as large as the initial value. D) more than three times as large as the initial value. E) impossible to predict on the basis of this data

C) three times as large as the initial value.

During an isochoric process, the internal (thermal) energy of a gas decreases by 50 J. How much heat is added to the gas during this process? A) 50 J B) 25 J C) 0 J D) -50 J E) -25 J

D) -50 J

Thermal efficiency (non-Carnot) is A) Q - W. B) Q/T. C) 1 - Tcold/Thot. D) 1 - Qcold/Qhot. E) Q/m.

D) 1 - Qcold/Qhot.

What is the maximum efficiency of an engine operating between 500 K and 300 K? A) 60% B) 50% C) 30% D) 40% E) 20%

D) 40%

1.50 moles of an ideal monatomic gas are initially at a temperature of 317 K. If the gas gains 2730 J of heat and performs 780 J of work, what is its final temperature? A) 756 K B) 526 K C) 687 K D) 421 K E) 359 K

D) 421 K

What is meant by ʺthe heat death of the universeʺ? A) The radiation from the stars will continuously heat up the universe. B) Some day the sun will cease to provide electromagnetic radiation. C) The universe will end in a giant inferno. D) The universe will reach thermal equilibrium. E) Some day the sun will explode and we will all burn.

D) The universe will reach thermal equilibrium.

A gas is quickly compressed in an isolated environment. During the event, the gas exchanged no heat with its surroundings. This process is A) isobaric. B) isometric. C) isothermal. D) adiabatic.

D) adiabatic.

An ideal monatomic gas undergoes a reversible expansion to 1.5 times its original volume. In which of these processes does the gas perform the least amount of work? A) if the pressure increases in proportion to the volume B) if the pressure decreases in proportion to the volume C) at constant pressure D) adiabatically E) at constant temperature

D) adiabatically

An ideal gas is compressed to one-half its original volume during an isothermal process. The final pressure of the gas A) increases to less than twice its original value. B) increases to more than twice its original value. C) does not change. D) increases to twice its original value.

D) increases to twice its original value.

A gas is confined to a rigid container that cannot expand as heat energy is added to it. This process is A) isothermal. B) adiabatic. C) isobaric. D) isometric. E) isentropic.

D) isometric.

The process shown on the p-V graph in Fig. 12-6 is an A) isotherm. B) isobaric. C) adiabatic. D) isometric.

D) isometric.

The work done by the gas is negative for an A) isometric process. B) isothermal expansion. C) adiabatic expansion. D) isothermal compression.

D) isothermal compression.

A gas is expanded to twice its original volume with no change in its temperature. This process is A) isometric. B) adiabatic. C) isentropic. D) isothermal. E) isobaric.

D) isothermal.

The molar specific heat is the amount of heat required to raise the temperature of what amount of matter by one unit of temperature? A) two moles of a substance B) one molecule of a substance C) one unit of mass of a material D) one mole of a substance E) one tooth

D) one mole of a substance

Consider two cylinders of gas identical in all respects except that one contains O2 and the other He. Both hold the same volume of gas at STP and are closed by a movable piston at one end. Both gases are now compressed adiabatically to one-third their original volume. Which gas will show the greater temperature increase? A) the O2 B) neither; both will show the same increase C) impossible to tell from the information given D) the He

D) the He

When temperature is plotted against entropy, the area under the process path is equal to A) the change in internal energy. B) the work done. C) the heat added less the work done. D) the heat transferred.

D) the heat transferred.

) An irreversible engine operating between the temperatures of 550 K and 300 K extracts 1.20 kJ of heat from the hot reservoir and produces 0.450 kJ of work. How much entropy is created in the process? A) 0.73 J/K B) 0.68 J/K C) 0.44 J/K D) 0 J/K E) 0.32 J/K

E) 0.32 J/K

The coefficient of linear expansion of steel is 12 × 10-6 K-1. What is the change in length of a 25-m steel bridge span when it undergoes a temperature change of 40 K? A) 2.0 cm B) 1.8 cm C) 1.6 cm D) 1.4 cm E) 1.2 cm

E) 1.2 cm

A solid concrete wall 4.0 m by 2.4 m and 30 cm thick, with a thermal conductivity of 1.3 W/(m ∙K), separates a basement at 18°C from the ground outside at 6°C. How much heat flows through the wall in one hour? A) 5.0 kJ B) 1.8 kJ C) 5.0 MJ D) 500 J E) 1.8 MJ

E) 1.8 MJ

) What is the temperature of 3.0 moles of gas at a pressure of 250 kPa held in a volume of 15 L? A) 200 K B) 300 K C) 250 K D) 350 K E) 150 K

E) 150 K

The figure shows a graph of the temperature of a pure substance as a function of time as heat is added to it at a constant rate in a closed container. If LF is the latent heat of fusion of this substance and LV is its latent heat of vaporization, what is the value of the ratio LV/LF? A) 1.5 B) 4.5 C) 7.2 D) 5.0 E) 3.5

E) 3.5

A quantity of an ideal gas is kept in a rigid container of constant volume. If the gas is originally at a temperature of 19°C, at what temperature will the pressure of the gas double from its base value? A) 122°C B) 273°C C) 38°C D) 91°C E) 311°C

E) 311°C

A sample of an ideal gas is heated and its Kelvin temperature doubles. What happens to the average speed of the molecules in the sample? A) It does not change. B) It doubles. C) It halves. D) It is sqrt(1/ 2) times smaller. E) It is sqrt(2) times as large.

E) It is sqrt(2) times as large

The type of heat transfer that occurs between a stove and a pot placed on it is A) convective. B) evaporation. C) countercurrent. D) radiative. E) conductive.

E) conductive.

The process whereby heat flows by the mass movement of molecules from one place to another is referred to as A) radiation. B) conduction. C) evaporation. D) inversion. E) convection.

E) convection.

The internal energy of an ideal gas depends on A) its volume. B) its pressure. C) its temperature and pressure. D) its temperature, pressure, and volume. E) its temperature.

E) its temperature.

The point in the phase diagram where the fusion curve, the vapor pressure curve, and the sublimation curve join is called the A) double point. B) critical point. C) boiling point. D) melting point. E) triple point.

E) triple point.

A Carnot cycle consists of A) two isobars and two isotherms. B) four isotherms. C) two adiabats and two isobars. D) four adiabats. E) two adiabats and two isotherms.

E) two adiabats and two isotherms.