Deck 7: Second Law of Thermodynamics: and You Cant Even Break Even

Question 1

Large amounts of material can often be seen rising from the cooling towers often seen at steam- electric power plants. These emissions are mostly

A) carbon dioxide.
B) water vapor, i.e., steam.
C) soot.
D) radioactive waste.
E) oxides of sulfur.

Answer 1

water vapor, i.e., steam.

Question 2

Which method of fueling your car is likely to be more energy efficient, and why: gasoline used in a standard car engine or electricity taken from a coal- fueled generating plant and stored in lightweight car batteries? Assume that the batteries convert electricity to work at 100% efficiency, and that electricity is transported from the power plant to the car at 100% efficiency.

A) Gasoline used in a standard car engine, because a car engine burns its fuel directly in the automobile rather than miles away at the power plant.
B) Electricity from a coal- fired generating plant, because such a plant runs at higher energy- efficiency than does a car engine.
C) It wouldn't make any difference, because both the car engine and the generating plant are heat engines and are thus subject to the second law of thermodynamics.
D) Electricity from a coal- fired generating plant, because a car engine is a heat engine, and must follow the second law of thermodynamics, whereas a coal- fired generating plant is not.
E) Gasoline used in a standard car engine, because a car engine's fuel burns hotter and more efficiently than does the coal in a coal- fired power plant.

Answer 2

Electricity from a coal- fired generating plant, because such a plant runs at higher energy- efficiency than does a car engine.

Question 3

Which of these uses thermal energy to do work?

A) a person walking uphill
B) a hot air balloon
C) an electric heater
D) All of the above.
E) None of the above.

Answer 3

a hot air balloon

Question 4

Company X increases its profits every year by $50 million. Its growth in profits is

A) Linear.
B) Parabolic.
C) Exponential.
D) Quadratic.

Question 5

A particular automobile operates at an efficiency of 10%. Suppose that 20 gallons of gasoline are put into the auto's tank. Of this 20 gallons, how much will be "wasted" , i.e., how much will be consumed to produce exhaust heat and in other ways that do not actually get the car down the road?

A) 10 gallons
B) 20 gallons
C) 19 gallons
D) 2 gallons
E) 18 gallons

Question 6

According to the second law of thermodynamics,

A) energy process that uses thermal energy to do work must have a thermal energy exhaust.
B) thermal energy flows spontaneously from hot objects to cold objects.
C) the total entropy of all the participants in any physical process cannot decrease.
D) All of the above.
E) None of the above.

Question 7

Country X increases its population by 5% per year. How long will it be before its population doubles?

A) It is impossible to answer this without knowing country X's population.
B) 35 years
C) 14 years
D) 20 years
E) 10 years

Question 8

During each cycle of its operation, a certain heat engine does 40 joules of work while exhausting 160 joules of thermal energy to the environment. The energy efficiency of this heat engine is

A) 80%.
B) 75%.
C) 25%.
D) 20%.
E) None of the above.

Question 9

Company X increases its profits every year by 1% million. Its growth in profits is

A) Linear.
B) Exponential.
C) Parabolic.
D) Quadratic.

Question 10

The "law of heat flow" is one form of

A) insanity.
B) the second law of thermodynamics.
C) the law of conservation of energy.
D) the ideal gas laws.
E) the law of inertia.

Question 11

Lilies in a certain pond double their total lake area covered every week. One day you notice that the pond is 1/8 covered with lilies. How long will it be before the pond is totally covered with lilies?

A) 6 weeks
B) 8 weeks
C) 4 weeks
D) 3 weeks
E) It is impossible to answer this without knowing the total area of the pond.

Question 12

A large coal- fired electric generating plant burns about 1000 kg [one tonne] of coal every 10 seconds. About much of the tonne actually goes into producing electric energy?

A) 40 kg
B) 800 kg
C) 400 kg
D) 990 kg
E) 100 kg

Question 13

Is a fuel- cell vehicle properly described as a "heat engine"?

A) No, because it converts electric energy directly into chemical energy.
B) No, because it converts chemical energy directly to electric energy.
C) Yes, because it uses thermal energy to produce electricity.
D) Yes, because it uses chemical energy to create electric energy.
E) Yes, because it uses thermal energy to do work.

Question 14

"Hybrid drive" automobiles use

A) natural gas fuel stored at high pressure.
B) hydrogen fuel that burns much like gasoline within an engine that drives the wheels.
C) small batteries that energize a small gasoline engine that drives the wheels.
D) a small gasoline engine that drives an electric generator.
E) large storage batteries that are recharged by plugging them into a wall socket.

Question 15

According to the second law of thermodynamics,

A) the entropy of all the participants in any physical process cannot decrease.
B) kinetic energy cannot be entirely converted into thermal energy.
C) work cannot be entirely converted into thermal energy.
D) the entropy of all the participants in any physical process cannot increase.
E) the amount of energy going into any thermodynamic process must equal the amount coming out of that process.

Question 16

The fuel that goes into a "hybrid drive" vehicle is

A) electricity.
B) natural gas.
C) gasoline.

Question 17

Compared with the efficiency of a typical steam- electric generating plant, the efficiency of a typical hydro- electric generating plant is

A) smaller, because only a small amount of the energy in the water behind a dam can be converted into electricity.
B) about the same, because both are heat engines and so both have the large inefficiency implied by the second law of thermodynamics.
C) greater because a hydro- electric plant is not a heat engine and so it does not have the large inefficiency implied by the second law of thermodynamics.
D) smaller because a steam- electric converts thermal energy into non- thermal forms and the second law of thermodynamics implies that this is a highly efficient process.
E) greater because a hydro- electric plant uses the sun as its source of energy, rather than hard- to- obtain fossil fuels.

Question 18

Which of the following is one of the drawbacks of the automobile engine?

A) CO is injected into the atmosphere
B) the internal combustion engine has all of these drawbacks
C) low efficiency
D) CO₂ is injected into the atmosphere
E) the internal combustion engine has none of these drawbacks

Question 19

Which of the following is the main reason for the fact that hydroelectric power plants are far more efficient than coal- fired electric power plants?

A) Hydroelectric plants have far fewer moving parts.
B) Coal is only partially combustible, due to the presence of large amounts of impurities.
C) Since the hydroelectric plant is not a heat engine, it is not restricted by the second law of thermodynamics.
D) The law of conservation of energy tells us that heat engines, such as hydroelectric plants, are more efficient than other forms of energy conversion.
E) Actually, hydroelectric plants are not significantly more efficient than coal- fired plants.

Question 20

A day during which the atmospheric temperature was 5°C would be described as

A) a nice day.
B) a hot day.
C) a cold day, but not freezing.
D) below freezing.
E) None of the above, because atmospheric temperatures never gets this cold.

Question 21

As a leaf grows, it becomes more organized. Does this process violate the law of entropy?

A) No, because the sugars and other molecules of the leaf are formed at a high temperature, resulting in an overall increase of the total entropy.
B) Yes; in fact, it is known that the law of entropy does not apply to biological processes such as the growth of a leaf, or biological evolution.
C) No, because total energy is conserved in this process, despite the increased organization of the leaf.
D) No, because the O₂ that is emitted during photosynthesis has greatly increased entropy, resulting in an overall increase of the total entropy.
E) No, because the radiation passing through the leaf during this process increases its entropy, so that the total entropy increases.

Question 22

Which one of the following is responsible for the "one- way" nature of time, i.e., for the distinction between past and future?

A) the law of conservation of energy
B) the law of inertia
C) the electromagnetic force
D) the gravitational force
E) the second law of thermodynamics

Question 23

In the operation of a steam- electric generating plant, the thermal energy input occurs

A) in the condenser.
B) at the point where the hot steam pushes against the turbine.
C) at the point where the energy from the furnace is transferred into the boiler.
D) in the electric generators.
E) at the point where the fossil or other fuel is shipped into the plant area.

Question 24

During each cycle of its operation, a certain gasoline engine consumes 500 joules of chemical energy, while exhausting 300 joules of thermal energy to the environment. The energy efficiency of this heat engine is

A) 67%.
B) 40%.
C) 60%.
D) 20%.
E) None of the above.

Question 25

During each cycle of operation, the thermal energy input to a heat engine is 400 J and the exhaust is 300 J. This engine's efficiency is

A) 25%.
B) 100%.
C) 75%.
D) 50%.
E) 0%.

Question 26

The "law of heat engines" is one form of

A) the law of inertia.
B) the second law of thermodynamics.
C) the ideal gas laws.
D) the law of conservation of energy.
E) idiocy.

Question 27

What is the efficiency of a heat engine whose thermal energy input is 400 J and whose exhaust is 300 J?

A) 50%
B) 25%
C) 75%
D) 175%
E) 33%

Question 28

Which of the following would be "linear" growth of your bank savings account?

A) Growth by 7% every year
B) Growth by $1000 every year
C) Both of the above.
D) Neither of the above

Question 29

Lilies in a certain pond double their total lake area covered every week. The growth of the lilies is

A) Linear.
B) Exponential.
C) Parabolic.
D) Quadratic.

Question 30

Country X's population is doubling every 10 years. What is its rate of population growth?

A) It is impossible to answer this without knowing country X's population.
B) 2% per year
C) 7% per year
D) 10% per year
E) 14% per year

Question 31

Is it physically possible [even though it might be impractical to actually carry out] to drive a ship across the ocean by using the thermal energy in the surface waters of the ocean? That is, could this be done without violating any principle of physics?

A) Yes, by exhausting the unused thermal energy into the stratosphere or into the deep ocean, where the temperature is cooler than that of the ocean's surface.
B) No, because this process would violate the law of conservation of energy.
C) Yes, by exhausting the unused thermal energy into Earth's lower atmosphere, where the temperature is warmer than that of the ocean's surface.
D) No, because this process would violate the second law of thermodynamics.
E) No, because there is no thermal energy in the ocean.

Question 32

The most energy- efficient form of transportation in the animal kingdom is a human on a bicycle. A basic physics principle that helps explain the bicycle's high efficiency [relative to other technologies for human transportation] is

A) the second law of thermodynamics.
B) the work- energy principle.
C) the law of gravity.
D) the electromagnetic force law.
E) the law of conservation of energy.

Question 33

"Smokestacks" [i.e., the tall stacks] attached to many electric generating plants emit mostly

A) soot.
B) water vapor.
C) carbon dioxide.
D) cow dung.
E) oxides of sulfur.

Question 34

In the operation of a steam- electric generating plant, the work output [from thermal energy to work] occurs

A) in the condenser.
B) at the point where the energy from the furnace is transferred into the boiler.
C) at the point where the hot steam pushes against the turbine.
D) at the point where the fossil or other fuel is shipped into the plant area.
E) in the electric generators.

Question 35

Suppose an automobile's fuel could be made to burn hotter without harming the engine's operation. Would you still get the same amount of useful work from each gallon of gasoline?

A) You would get less work, because heat engines run less efficiently when the input temperature is higher.
B) It wouldn't make any difference, because the efficiency is related only to the amount of input energy, and not to the temperature of this energy.
C) You would get more work, because heat engines are more efficient at converting thermal energy into work when the input temperature is higher.
D) You would get less work, because less chemical energy would be used at the higher temperature.
E) You would get more work, because heat engines are more efficient at converting chemical energy into thermal energy when the temperature is higher.

Question 36

The temperature of a nice day is about

A) 25°C.
B) 10°C.
C) 50°C.
D) 70°C.
E) 0°C.

Question 37

In one cycle of operation, the thermal energy input to a particular heat engine is 200 joules and the exhaust is 80 joules. The efficiency of this engine is

A) impossible to determine from the given information.
B) 40 percent.
C) 80 percent.
D) 20 percent.
E) 60 percent.

Question 38

Which of the following best represents the energy transformations in a coal- fired electric power plant?

A) gravitational ·kinetic ·electromagnetic
B) chemical ·kinetic ·thermal ·electromagnetic
C) electromagnetic ·thermal ·kinetic
D) chemical ·thermal ·kinetic ·electromagnetic
E) radiant ·kinetic ·electromagnetic ·thermal

Question 39

According to the second law of thermodynamics,

A) thermal energy will not flow spontaneously.
B) thermal energy flows spontaneously from high temperatures to low temperatures.
C) work cannot be entirely converted into thermal energy.
D) thermal energy flows spontaneously from low temperatures to high temperatures.
E) the amount of energy going into any thermodynamic process exactly equals the amount coming out.

Question 40

Suppose an car engine could be made to burn at a higher temperature, without harming or altering any other part of the engine's operation. At the higher temperature, the engine would

A) have the same efficiency but be able to operate at a higher power.
B) still consume the same amount of gasoline per kilometer traveled.
C) have a lower efficiency.
D) have a higher efficiency.
E) consume more gasoline per kilometer traveled.

Question 41

A day during which the atmospheric temperature was 40°C would be described as

A) a nice day.
B) below freezing.
C) a hot day.
D) above boiling.
E) a cold day, but not freezing.

Question 42

Does biological evolution violate the law of entropy, and why or why not?

A) No, because Earth's organisms actually increase their own entropy during evolution, despite the appearance that they are becoming better organized.
B) No, because the increase in the entropy of the radiation passing through living organisms is greater than the decrease in the entropy of those organisms.
C) No, because the energy increase of Earth's living organisms is exactly balanced by the energy decrease of the radiation flowing through those organisms.
D) Yes, because this law is violated in situations involving energy from the sun.
E) Yes, because this law is violated when new species are created on Earth.

Question 43

Which of the following is not a possible energy source for a steam- electric generating plant?

A) solar energy
B) fossil fuels
C) wood
D) fissionable material such as uranium
E) All of the above are possible energy sources.

Question 44

The second law of thermodynamics implies that

A) in physical process in which heat is produced, the total amount of energy is reduced by an amount equal to amount of heat produced.
B) from the microscopic point of view, thermal energy is just kinetic energy of individual atoms and molecules.
C) thermal energy cannot be entirely converted into non- thermal forms of energy.
D) non- thermal forms of energy cannot be entirely converted into thermal forms of energy.
E) in every physical process, the total amount of energy must remain unchanged.

Question 45

A system's "entropy" is

A) the amount of microscopic disorganization in the system.
B) the amount of microscopic work the system can do.
C) the amount of force the system could exert.
D) the amount of work the system can do.
E) the amount of thermal energy in the system.

Question 46

Which laws of physics, if any, distinguish between the backward and the forward direction in time?

A) None.
B) The second law of thermodynamics but not the law of conservation of energy.
C) The law of conservation of energy and the second law of thermodynamics.
D) The law of conservation of energy but not the second law of thermodynamics.
E) Newton's law of motion.

Question 47

When the inside of a refrigerator is cooled, does thermal energy flow from hot to cold, or is it from cold to hot? Does this happen spontaneously, or is outside assistance required?

A) From cold to hot. Since this is against the normal flow of thermal energy, outside assistance is required.
B) From cold to hot. Since this is the normal way that thermal energy flows, no outside assistance is needed.
C) Only the Shadow knows.
D) From hot to cold. Since this is against the normal flow of thermal energy, outside assistance is required.
E) From hot to cold. Since this is the normal way that thermal energy flows, no outside assistance is needed.

Question 48

In the operation of a steam- electric generating plant, the exhaust, or thermal energy output, occurs

A) at the point where the energy from the furnace is transferred into the boiler.
B) in the electric generators.
C) at the point where the hot steam pushes against the turbine.
D) in the University Chancellor's office.
E) as part of the operation of the condenser.

Question 49

The main limitation on the efficiency of heat engines is due to

A) friction in the moving parts.
B) the first law of thermodynamics.
C) environmental extremists.
D) reaction forces due to Newton's third law.
E) the second law of thermodynamics.

Question 50

A block of wood slides to a stop along a tabletop. In this process,

A) energy remains unchanged but energy quality is gained.
B) energy is lost.
C) both energy and energy quality remain unchanged but thermal energy is lost while kinetic energy is gained.
D) energy remains unchanged but energy quality is lost.
E) both energy and energy quality remain unchanged but thermal energy is gained while kinetic energy is lost.

Question 51

Which of the following is not a heat engine?

A) automobile engine
B) hydro- electric generating plant
C) nuclear electric power plant
D) coal- fired electric generating plant
E) steam locomotive

Question 52

The principle stating that the work output of a heat engine must be less than its total energy input is called

A) the law of conservation of energy.
B) the kinetic principle.
C) the second law of thermodynamics.
D) the first law of thermodynamics.
E) Nonsense-- there is no such physical law.

Question 53

Which of the following is an "irreversible" process?

A) A block of wood sliding to a stop along a tabletop.
B) A perfectly elastic ball that falls and rebounds from the floor back to its initial height.
C) Both of the above.
D) Neither of the above.

Question 54

An electric generating plant produces 400 MW of electric power while operating at 40% efficiency. The rate at which this plant consumes energy [in the form of the thermal energy obtained by burning the coal that is fed into the plant] is

A) 240 MW.
B) 1000 MW.
C) 1400 MW.
D) 160 MW.
E) 600 MW.

Question 55

The main reason for the large inefficiency of the automobile is

A) friction in the moving parts.
B) the kinetic principle.
C) the second law of thermodynamics.
D) the first law of thermodynamics.
E) unburned hydrocarbons.

Question 56

Does the growth of a leaf violate the law of entropy, and why or why not?

A) No, because the leaf actually increases its own entropy in this process, despite the appearance that it is becoming better organized.
B) No, because the energy increase of the leaf is exactly balanced by the energy decrease of the radiation flowing through the leaf.
C) No, because the increase in the entropy of the radiation passing through the leaf is greater than the decrease in the entropy of the leaf itself.
D) Yes, because this law is violated in situations involving energy from the sun.
E) Yes, because this law is violated by living organisms.

Question 57

What is the work output of a heat engine whose thermal energy input is 400 J and whose exhaust is 300 J?

A) 700 J
B) 300 J
C) 100 J
D) 400 J
E) 200 J

Question 58

When you touch a piece of ice,

A) work flows from the ice to your hand.
B) thermal energy flows from your hand to the ice.
C) chemical energy flows from the ice to your hand.
D) thermal energy flows from the ice to your hand.
E) work flows from your hand to the ice.

Question 59

Suppose you viewed a movie that was running backwards. You would see lots of odd things happening: streams would flow uphill, and so forth. If these odd "backward- moving" things actually happened in nature, which principle or principles of physics would be violated?

A) Newton's law of motion
B) The second law of thermodynamics
C) Both of the above.
D) The law of conservation of energy
E) All of the above.

Question 60

A typical automobile consumes about 70 kW of power from the gas tank. How many 100- watt light bulbs could this light up, if the energy were used to light electric bulbs rather than to run the car?

A) 7 bulbs
B) 7000 bulbs
C) 700 bulbs
D) 70 bulbs
E) This question cannot be answered without knowing the amount of time the car is being driven at this power.

Question 61

The "efficiency" of a heat engine is defined to be

A) work output divided by thermal energy output.
B) thermal energy output divided by thermal energy input.
C) thermal energy output divided by work input.
D) work output divided by thermal energy input.

Question 62

When a fuel cell operates, the energy transformation within the cell itself is

A) chemical energy to thermal energy.
B) chemical energy to electric energy.
C) thermal energy to kinetic energy.
D) electric energy to chemical energy.
E) thermal energy to electric energy.

Question 63

The most efficient form of locomotion in the animal kingdom is

A) a human walking.
B) a bird flying.
C) a propeller- driven airplane.
D) a human on a bicycle.
E) railroad trains.

Question 64

A fundamental physical reason for the bicycle's high efficiency as a transportation device is

A) it is a wheeled vehicle.
B) it is not a heat engine.
C) Both of the above.
D) it is a heat engine, but one that does not burn fossil fuels.
E) Nonsense, trains and airplanes are actually more efficient than bicycles.

Question 65

The overall energy efficiency of a typical automobile is closest to

A) 40%.
B) 60%.
C) 90%.
D) 2%.
E) 10%.

Question 66

Entropy is best defined as

A) energy that is due to its temperature.
B) the capacity to do work.
C) microscopic disorganization.
D) energy that is due to chemical structure.
E) microscopic organization.

Question 67

About how much CO₂ comes out of the stack of a coal- burning plant that consumes one ton of coal?

A) None, because the CO² is precipitated as a solid.
B) Anywhere from 1 ton to about 10 tons, depending on the design of the plant.
C) About 3 tons.
D) Much less than one ton.
E) About 1 ton.

Question 68

Conventional automobile efficiencies cannot conceivably be higher than about 25%, even with perfect engineering. This is due to

A) air resistance plus road friction.
B) road friction.
C) the law of conservation of energy.
D) the second law of thermodynamics.
E) frictional loses inside the car plus unburned hydrocarbons.

Question 69

Which of the following would be "exponential" growth of your bank savings account?

A) Growth by 7% every year
B) Growth by $1000 every year
C) Both of the above.
D) Neither of the above

Question 70

Large curved cooling towers can often be seen at

A) steam- electric power plants.
B) nuclear power plants.
C) Both of the above.
D) hydro- electric plants.
E) All of the above.

Question 71

The basic energy transformation that takes place in all heat engines is

A) kinetic to thermal.
B) chemical to thermal.
C) chemical to electric.
D) non- thermal to thermal.
E) thermal to non- thermal.

Question 72

For every 100 gallons of gasoline you use in your car, the amount that actually goes into moving the car down the road is roughly

A) 50 gal.
B) 10 gal.
C) 2 gal.
D) 75 gal.
E) 98 gal.

Question 73

When you touch a warm pot on the stove,

A) work flows from your hand to the pot.
B) thermal energy flows from your hand to the pot.
C) thermal energy flows from the pot to your hand.
D) electric energy flows from the pot to your hand.
E) work flows from the pot to your hand.

Question 74

Which type of generating plant would you expect to be more energy efficient, steam- electric or hydroelectric?

A) Hydroelectric, because it is not a heat engine and so is not restricted by the second law of thermodynamics.
B) Steam- electric, because there is so much more energy per ton in fossil fuels than in water behind a dam.
C) Hydroelectric, because the lake and river water provides natural cooling for the exhaust.
D) Steam- electric, because it can have a very high operating temperature due to having a large and thick boiler.
E) Hydroelectric, because there is so much energy in a large lake raised up behind a dam.

Question 75

Nuclear and fossil fuel generating plants differ in their need for a

A) smoke- stack.
B) cooling lake or tower.
C) boiler.
D) condenser.
E) All of the above.

Question 76

The most energy- efficient form of transportation in the animal kingdom is a human on a bicycle. A basic physics principle that helps explain the bicycle's high efficiency is

A) the electromagnetic force law.
B) the law of inertia.
C) the law of gravity.
D) the work- energy principle.
E) the law of conservation of energy.

Question 77

The biggest reason why heat engines are far from 100% efficient is

A) gravitational forces.
B) gremlins.
C) the second law of thermodynamics.
D) friction.
E) the first law of thermodynamics.