Winter 2012 Phys202

Front 1

Temperature

Back 1

-a measure of how hot or cold something is
-a measure of the average kinetic energy of the molecules a system

Front 2

Thermocouple

Back 2

a junction between two dissimilar metals that produces a voltage related to the temperature

Front 3

Constant-Volume Gas Thermometer

Back 3

A constant-volume gas thermometer depends only on the properties of an ideal gas, which do not change over a wide variety of temperatures. Therefore, it is used to calibrate thermometers based on other materials.

Front 4

Thermal Equilibrium

Back 4

Two objects are in thermal equilibrium if, when placed in thermal contact, no energy flows from one to another.

Front 5

The Zeroth Law of Thermodynamics

Back 5

The zeroth law of thermodynamics says that if two systems are each in thermal equilibrium with a third system, they are also in thermal equilibrium with each other.
If system A is in thermal equilibrium with system C and system B is in thermal equilibrium with system C, then system A is in thermal equilibrium with system B.
If the zeroth law was not true it would not be possible to determine the temperature of a system.

Front 6

Linear expansion

Back 6

occurs when an object is heated

Front 7

Volume expansion

Back 7

similar to linear expansion except that it is relevant for liquids and gases as well as solids

Front 8

Thermal Stress

Back 8

A material may be fixed at its ends and therefore be unable to expand or contract when the temperature changes. It will then experience large compressive or tensile stress—thermal stress—when its temperature changes.
These stresses can cause the object to buckle or break. They can also be useful, e.g. in hot riveting.

Front 9

Liquefaction Temperature

Back 9

The long-range interactions between the molecules of a real gas cause it to liquefy if it is cooled to the liquefaction temperature.

Front 10

Boyle's Law

Back 10

The volume of a given amount of gas is inversely proportional to the pressure as long as the temperature is constant.

V ∝ 1/P

Front 11

Charle's Law

Back 11

The volume of a given amount of gas is directly proportional to the absolute temperature as long as the pressure is constant.

V ∝ T

Front 12

Gay-Lussac's Law

Back 12

The pressure of a given amount of gas is directly proportional to the absolute temperature as long as the volume is constant.

P ∝ T

Front 13

The Ideal Gas Law

Back 13

PV = nRT

Front 14

Boltzmann’s constant

Back 14

1.38 × 10-²³ J/K

Front 15

Heat

Back 15

Heat is energy transferred from one system to another because of a difference in temperature.
The energy can be transferred by conduction, convection, and/or radiation.

Front 16

Work

Back 16

Work is energy transferred from one system to another by mechanical means, not due to a difference in temperature.

Front 17

Internal Energy

Back 17

The molecules of a system are moving and so have kinetic energy and there are long range forces between the molecules so they have potential energy.

The total of all the energy of all the molecules in a system is its internal energy.

Front 18

Change in Internal Energy

Back 18

When heat flows into or out of a system without any other energy being transferred to or from the system, the internal energy of the system increases or decreases. This change in internal energy may be a change in translational kinetic energy, in which case the temperature changes, and/or a change in other types of kinetic energy, and/or a change in potential energy.
Similarly, when work is done on or by a system its internal energy changes.

Front 19

Convection

Back 19

Convection occurs when heat flows by the mass movement of molecules from one place to another in the form of convection currents. Convection can only occur in a fluid.

Front 20

Radiation

Back 20

All objects constantly emit and absorb radiation in the form of electromagnetic waves (light).
Hotter objects emit more of their radiation at shorter wavelengths; objects at everyday temperatures emit most of their radiation as infrared light (also called thermal or heat radiation).

Front 21

Stefan-Boltzmann Law

Back 21

The rate at which an object emits or absorbs radiation is proportional to its surface are, the nature of its surface, and the fourth power of the absolute temperature.

σ = 5.67 × 10^-8 W/m² ⋅ K⁴

Front 22

Emissivity

Back 22

The emissivity ε is a number between 0 and 1 characterizing the surface; dark, dull objects have an emissivity near 1, while light, shiny ones have an emissivity near 0. It is the same for absorption; a good emitter is also a good absorber. A perfect emitter (ε = 1) is called a blackbody.

Front 23

Thermography

Back 23

the detailed measurement of radiation from an object—can be used in medical imaging. Warmer areas may be a sign of tumors or infection; cooler areas on the skin may be a sign of poor circulation

Front 24

Thermodynamics

Back 24

the study of processes in which energy is transferred as heat and/or as work.
A process takes a system from one state to another. We will assume the system remains in equilibrium during the process.

Front 25

The First Law of Thermodynamics

Back 25

The change in internal energy of a closed system is equal to the energy added to the system as heat minus the work done by the system on its surroundings.
∆U = Q - W
This is the law of conservation of energy, written in a form useful to systems involving heat transfer.
Heat flow into the system is positive; heat flow out of the system is negative. Work done by the system on the surroundings is positive; work done on the system by the surroundings is negative.

Front 26

Isobaric Process

Back 26

An isobaric process occurs at constant pressure.
The work done equals the pressure times the change in volume.

Front 27

Isochoric Process

Back 27

An isochoric (or isovolumetric) process occurs at constant volume. No work is done during the process. The change in internal energy equals the heat exchanged with the surroundings.
∆U = Q

Front 28

Isothermal Process

Back 28

An isothermal process is one in which the temperature does not change because the system is in contact with a heat reservoir.

Front 29

Adiabatic Process

Back 29

An adiabatic process is one in which there is
no heat flow into or out of the system.
This may be because the system is isolated from the surroundings by insulating walls or because the process occurs so quickly there is no time for an appreciable amount of heat to be transferred between the system and the surroundings.
Since Q = 0 the first law becomes ∆U = -W . If work is done on the system the internal energy increases; it decreases when work is done by the system.

Front 30

Adiabatic Expansion or Compression

Back 30

During an adiabatic expansion of a gas work is done by the gas on the surroundings and the internal energy of the gas decreases. Therefore the temperature of the gas also decreases.
During an adiabatic compression, work is done on the gas, the internal energy of the gas increases, and its temperature increases.

Front 31

Metabolic Rate

Back 31

the rate at which internal energy is transformed in the body

Front 32

Heat Flow Statement of the 2nd Law

Back 32

Heat can flow spontaneously from a hot object to a cold object; it will not flow spontaneously from a cold object to a hot object

Front 33

Heat Engines
It is easy to produce internal energy using work (for example, by friction), but how does one produce work using internal energy?

Back 33

It is easy to produce internal energy using work (for example, by friction), but how does one produce work using internal energy?
With a heat engine; mechanical energy can be obtained from internal energy only when heat can flow from a higher temperature to a lower temperature.
We will discuss only engines that run in a repeating cycle; the change in internal energy of the engine over a cycle is zero, as the system returns to its initial state.

Front 34

The Otto Cycle

Back 34

two adiabatic paths alternating with two constant- volume paths

Front 35

Heat Engine Statement of the 2nd Law

Back 35

No device is possible whose sole effect is to transform a given amount of heat completely into work.
No heat engine can have an efficiency of 100%.

Front 36

Refrigerators, Air Conditioners, and Heat Pumps

Back 36

These devices are essentially heat engines operating in reverse.
By doing work, heat is extracted from the cold reservoir and exhausted to the hot reservoir.

Front 37

Entropy

Back 37

Macroscopic definition—a measure of the amount of energy that is unavailable for doing work.
Microscopic definition—a measure of the amount of disorder of the molecules of a system.

Front 38

Entropy Statement of the Second Law

Back 38

For any process, the entropy of the universe never decreases.
The change in entropy of the universe is zero for a reversible process and positive for an irreversible process.
Natural processes tend to move toward a state of greater disorder.
In any natural process, some energy becomes unavailable to do useful work.

Front 39

Macrostates and Microstates

Back 39

A macrostate of a system is specified by giving its macroscopic properties – temperature, pressure, and so on.
A microstate of a system describes the position and velocity of every particle.
For every macrostate, there are one or more microstates.

Front 40

The Third Law of Thermodynamics

Back 40

It is impossible for the temperature of a system to reach absolute zero in a finite number of steps.


As the temperature approaches absolute zero, the entropy of the system approaches its minimum value.

Front 41

How does the size of a Celsius degree compare with the size of a Fahrenheit degree?
(a) They are the same size.
(b) A Celsius degree is 5/9 the size of a Fahrenheit degree.
(c) A Celsius degree is 9/5 the size of a Fahrenheit degree.
(d) A Celsius degree is 5/9 the size of a Fahrenheit degree minus 32 degrees.
(e) A Celsius degree is 9/5 the size of a Fahrenheit degree plus 32 degrees.

Back 41

(c) A Celsius degree is 9/5 the size of a Fahrenheit degree

Front 42

Two objects are in thermal equilibrium if:
(a) they are at the same temperature. they contain the same amount of heat.
(b) heat flows between them when they are placed in thermal contact.
(c) no heat flows between them when they are placed in thermal contact.

Back 42

(c) no heat flows between them when they are placed in thermal contact.

Front 43

A glass is filled to the brim with water. The temperature of the glass and the water is 20°C. What happens when the glass and water are heated to 60°C?
(a) They both expand so the water stays at the brim of the glass.
(b) The water expands more than the glass so it spills out.
(c) Only the water expands so it spills out.
(d) The glass expands more than the water so the water level drops.
(e) Only the glass expands so the water level drops.

Back 43

(b) The water expands more than the glass so it spills out

Front 44

Which of the following statements are true about absolute zero?
(Check all that are true.)
(a) Absolute zero is the coldest possible temperature.
(b) Absolute zero is the temperature at which all motion ceases.
(c) Absolute zero is the temperature at which an ideal gas would have zero volume.
(d) Absolute zero is the temperature at which an ideal gas would have zero pressure.

Back 44

(a) Absolute zero is the coldest possible temperature.
(c) Absolute zero is the temperature at which an ideal gas would have zero volume. Absolute zero is the temperature at which an ideal gas would have zero pressure.

Front 45

A balloon contains air at a temperature of 20°C and a pressure of 1 atm. What happens to the volume of the balloon when the temperature rises to 40°C? Assume air acts like an ideal gas and that the pressure remains constant.
(a) The volume remains constant.
(b) The volume increases by a factor of 2 (i.e. it doubles).
(c) The volume increases, but by a factor greater than 2.
(d) The volume increases, but by a factor less than 2.

Back 45

(d) The volume increases, but by a factor less than 2.

Front 46

Compare one mole of nitrogen (N2) gas and one mole of helium (He) gas.
(a) They have the same number of molecules and the same mass.
(b) They have the same number of molecules but different masses.
(c) They have the same mass but different numbers of molecules.
(d) They have different masses and different numbers of molecules.

Back 46

(b) They have the same number of molecules but different masses.

Front 47

Two identical cylinders contain an ideal gas at the same temperature. Cylinder B contains twice as much gas as cylinder A. How does the pressure of the gas in the two cylinders compare?
(a) The pressure of the gas in cylinder A is the same as the pressure of the gas in cylinder B.
(b) The pressure of the gas in cylinder A is twice the pressure of the gas in cylinder B.
(c) The pressure of the gas in cylinder A is half the pressure of the gas in cylinder B.
(d) It's impossible to answer the question without knowing the temperature and volume of the gas.

Back 47

(c) The pressure of the gas in cylinder A is half the pressure of the gas in cylinder B.

Front 48

Which of the following are postulates of the kinetic theory of gases?
(Check all that apply.)
(a) There are a large number of molecules moving with random speeds in random directions.
(b) The molecules are, on the average, far apart.
(c) The molecules obey the laws of classical mechanics.
(d) Collisions between the molecules are inelastic.

Back 48

(a) There are a large number of molecules moving with random speeds in random directions.
(b) The molecules are, on the average, far apart.
(c) The molecules obey the laws of classical mechanics.

Front 49

A cylinder contains a mixture of hydrogen (H2) and nitrogen (N2) gas at a temperature of 20°C. Compare the average kinetic energy and the average (rms) speeds of the molecules.
(a) Both types of molecules have the same average kinetic energy and the same average speed.
(b) Both types of molecules have the same average kinetic energy. The average speed of the hydrogen molecules is greater than that of the nitrogen molecules.
(c) Both types of molecules have the same average kinetic energy. The average speed of the nitrogen molecules is greater than that of the hydrogen molecules.
(d) The average kinetic energy and average speed of the hydrogen molecules is greater than the average kinetic energy and average speed of the nitrogen molecules.
(e) The average kinetic energy and average speed of the nitrogen molecules is greater than the average kinetic energy and average speed of the hydrogen molecules.

Back 49

(b) Both types of molecules have the same average kinetic energy. The average speed of the hydrogen molecules is greater than that of the nitrogen molecules.

Front 50

Compare the average (rms) speed of oxygen (O2) molecules at 400 K with their average (rms) speed at 100 K.
(a) The average speed at 400 K is four times greater than at 100 K.
(b) The average speed at 400 K is two times greater than at 100 K.
(c) The average speed at 100 K is two times greater than at 400 K.
(d) The average speed is the same at both temperatures.

Back 50

(b) The average speed at 400 K is two times greater than at 100 K.

Front 51

Which of the following statements about heat are always correct?
(Check all that apply.)
(a) Heat is the same as temperature.
(b) The hotter something is the more heat it contains.
(c) Two different objects are at different temperatures. The hot object contains more heat than the cold object.
(d) Heat is the transfer of energy due to a difference in temperature.

Back 51

(d) Heat is the transfer of energy due to a difference in temperature.

Front 52

Which of the following statements about internal energy are always correct?
(Check all that apply.)
(a) Internal energy is the same as heat.
(b) The hotter something is, the more internal energy it contains.
(c) Two different objects are at different temperatures. The hot object contains more internal energy than the cold object.
(d) Internal energy is the total kinetic and potential energy of the molecules of a system.

Back 52

(b) The hotter something is, the more internal energy it contains.
(d) Internal energy is the total kinetic energy of the molecules of a system.

Front 53

The temperature of a system always changes when heat flows into the system. True or false?

Back 53

False

Front 54

Why doesn't the temperature of a substance change during a phase change?
(a) Because no heat is being added to the substance during a phase change.
(b) Because the internal energy of the substance doesn't change during a phase change.
(c) Because only the potential energy of the molecules of the substance changes during a phase change.
(d) Because the substance expands while it changes phase. (e) Because no work is done during the phase change.

Back 54

(c) Because only the potential energy of the molecules of the substance changes during a phase change.

Front 55

Which will cause more severe burns to your hand: water at 100°C or an equal amount of steam at 100°C?
(a) water
(b) steam
(c) both the same
(d) it depends...

Back 55

(b) steam

Front 56

A hot piece of steel at 100°C is placed on a large block of ice at 0°C. Some but not all of the ice melts. What is the final equilibrium temperature of the steel?
(a) 0°C
(b) 100°C
(c) between 0°C and 100°C

Back 56

(a) 0°C

Front 57

What happens to the internal energy of a system when heat flows into the system?
(a) The internal energy increases.
(b) The internal energy decreases.
(c) The internal energy remains the same.
(d) The internal energy may increase or remain the same.
(e) The internal energy may increase, decrease, or remain the same.

Back 57

(e) The internal energy may increase, decrease, or remain the same.

Front 58

Which of the following are statements of the second law of thermodynamics?
(Check all that apply.)
(a) The change in internal energy of a heat engine equals the amount of heat that flows into minus the amount of work it performs.
(b) The transfer of energy as heat is always from hotter to colder objects.
(c) It is impossible for a heat engine, operating in a cycle, to transform heat entirely into work.
(d) Heat cannot be transformed into other kinds of energy.

Back 58

(b) The transfer of energy as heat is always from hotter to colder objects.
(c) It is impossible for a heat engine, operating in a cycle, to transform heat entirely into work.

Front 59

After one complete cycle the change in internal energy of a heat engine is:
(a) zero
(b) positive
(c) negative
(d) equal to the amount of heat that enters or leaves the engine

Back 59

(a) zero

Front 60

A Carnot or ideal engine is:
(a) an engine with 100% efficiency.
(b) an engine with the highest possible efficiency.
(c) an engine whose efficiency is independent of the temperature at which it operates.
(d) another name for a steam engine.
(e) another name for an internal combustion engine.

Back 60

(b) an engine with the highest possible efficiency

Front 61

A reversible process is one that
(a) can be performed in reverse.
(b) when performed in reverse returns the system to its original state.
(c) when performed in reverse returns the surroundings to their original state.
(d) when performed in reverse returns both the system and the surroundings to their original states.

Back 61

(d) when performed in reverse returns both the system and the surroundings to their original states.

Front 62

Which of the following are definitions of entropy? (Check all that apply.)
(a) Entropy is a measure of the amount of energy that is unavailable for doing work.
(b) Entropy is a measure of the amount of thermal energy in a system.
(c) Entropy is a measure of the amount of disorder of a system.
(d) Entropy is a measure of the amount of disorder of the molecules of a system.

Back 62

(a) Entropy is a measure of the amount of energy that is unavailable for doing work.
(d) Entropy is a measure of the amount of disorder of the molecules of a system.

Front 63

According to the second law of thermodynamics, for any process
(a) entropy never decreases.
(b) entropy never increases.
(c) the entropy of the universe never decreases.
(d) the entropy of the universe never increases.

Back 63

(c) the entropy of the universe never decreases.

Front 64

Which one of the following statements best describes a refrigerator from a thermodynamics point of view?
(a) A refrigerator moves heat from lower to higher temperature.
(b) A refrigerator uses work to move heat from lower to higher temperature.
(c) A refrigerator uses work to move heat from lower to higher temperature but the spontaneous flow of heat in a refrigerator is from higher to lower temperature.
(d) A refrigerator uses work to move heat from lower to higher temperature and the spontaneous flow of heat in a refrigerator is from lower to higher temperature.

Back 64

(c) A refrigerator uses work to move heat from lower to higher temperature but the spontaneous flow of heat in a refrigerator is from higher to lower temperature.

Front 65

According to the third law of thermodynamics why is it not possible to cool a system to absolute zero?
(a) Because it would take an infinite number of steps to do so.
(b) Because all motion stops at absolute zero.
(c) Because the entropy of the system would become zero at absolute zero.
(d) Because the entropy of the system would be minimum at absolute zero.

Back 65

(a) Because it would take an infinite number of steps to do so.

Front 66

A ray of light in air is incident on a plate of glass at an angle to the normal. Which of the following statements are true? (Check all that apply.)

(a) There is a reflected ray.
(b) There is a refracted ray.
(c) The angle of reflection equals the angle of incidence.
(d) The angle of refraction equals the angle of incidence.
(e) The refracted ray bends toward the normal.
(f) The refracted ray bends away from the normal.
(g) The light appears to travels slower in the glass than in the air.
(h) The light appears to travel faster in the glass than in the air.

Back 66

(a) There is a reflected ray.
(b) There is a refracted ray.
(c) The angle of reflection equals the angle of incidence.
(e) The refracted ray bends toward the normal
(g) The light appears to travel slower in the glass than in the air

Front 67

Which of the following describe the image formed by a concave mirror when the object is beyond the center of curvature? (Check all that apply.)
(a) real
(b) virtual
(c) upright
(d) inverted
(e) magnified
(f) diminished
(g) the same size as the object

Back 67

(a) real
(d) inverted
(f) diminished

Front 68

Which of the following describe the image formed by a concave mirror when the object is within the focal point? (Check all that apply.)
(a) real
(b) virtual
(c) upright
(d) inverted
(e) magnified
(f) diminished
(g) the same size as the object

Back 68

(b) virtual
(c) upright
(e) magnified

Front 69

Which of the following describe the image formed by a convex mirror? (Check all that apply)
(a) real
(b) virtual
(c) upright
(d) inverted
(e) magnified
(f) diminished
(g) the same size as the object

Back 69

(b) virtual
(c) upright
(f) diminished

Front 70

A ray of light is incident on a plane mirror. It makes an angle of 20° with the plane of the
mirror. Which one of the following correctly gives the angles of incidence and reflection?

(a) The angle of incidence is 20° and the angle of reflection is 20°.
(b) The angle of incidence is 70° and the angle of reflection is 70°.
(c) The angle of incidence is 20° and the angle of reflection is 70°.
(d) The angle of incidence is 70° and the angle of reflection is 20°.

Back 70

(b) The angle of incidence is 70° and the angle of reflection is 70°.

Front 71

What is the main difference between a real image and a virtual image.
(a) Rays of light come from a real image; they only appear to come from a virtual image.
(b) Rays of light come from a virtual image; they only appear to come from a real image.
(c) mA real image can be photographed; a virtual image cannot be photographed.
(d) A virtual image is inverted and a real image is upright.

Back 71

(a) Rays of light come from a real image; they only appear to come from a virtual image.

Front 72

Which of the following describe the image formed in a plane mirror? (Check all that apply.)
(a) real
(b) virtual
(c) upright
(d) inverted
(e) magnified
(f) diminished
(g) the same size as the object

Back 72

(b) virtual
(c) upright
(g) the same size as the object

Front 73

A. light with the highest frequency
B. electromagnetic waves with wavelengths longer than visible light
C. the complete range of different types of light
D. a particle of light
E. the speed of light
F. a light wave


( ). radio waves
( ). electromagnetic wave
( ). c
( ). electromagnetic spectrum
( ). gamma rays
( ). photon

Back 73

A. gamma rays
B. radio waves
C. electromagnetic spectrum
D. photon
E. c
F. electromagnetic wave

Front 74

Two point sources produce identical sound waves. Where do the waves interfere? (Neglect reflections.)
(a) Everywhere.
(b) Only where the waves are in phase.
(c) Only where the waves are completely out of phase.
(d) Both where the waves are in phase and completely out of phase

Back 74

(a) everywhere

Front 75

Two identical waves start from the same point and travel different paths to a second point where they interfere. When is the interference constructive?
(a) Always.
(b) Never.
(c) When the di!erence in path length is an integer multiple of the wavelength.
(d) When the di!erence in path length is an odd-integer multiple of half the wavelength

Back 75

(c) When the difference in path length is an integer multiple of the wavelength

Front 76

Rank from lowest to highest the pitch heard by an observer for a source of sound
- moving perpendicular to the observer.
- moving towards the observer.
- moving away from the observer

Back 76

1. moving away from the observer
2. moving perpendicular to the observer.
3. moving towards the observer.

Front 77

What are the boundary conditions for a pipe or tube open at both ends? (Check all that
apply.) Assume the length of the pipe or tube is much greater than its diameter.
(a) The ends must be pressure nodes.
(b) The ends must be pressure antinodes
(c) The ends must be displacement nodes.
(d) The ends must be displacement antinodes.

Back 77

(a) The ends must be pressure nodes.
(d) The ends must be displacement antinodes.

Front 78

What are the boundary conditions for a pipe or tube open at one end and closed at the other?
(Check all that apply.) Assume the length of the pipe or tube is much greater than its
diameter.
(a) The closed end must be a pressure node and the open end
must be a pressure antinode.
(b) The closed end must be a pressure antinode and the open
end must be a pressure node.
(c) The closed end must be a displacement node and the open
end must be a displacement antinode.
(d) The closed end must be a displacement antinode and the
open end must be a displacement node.

Back 78

(b) The closed end must be a pressure antinode and the open end must be a pressure node.
(c) The closed end must be a displacement node and the open end must be a displacement antinode.

Front 79

How does the fundamental frequency of a pipe open at both ends compare with the
fundamental frequency of a pipe open at one end and closed at the other?
(a) The fundamental frequencies are the same.
(b) The fundamental frequency of the pipe open at both ends is twice that of the pipe open
(c) The fundamental frequency of the pipe open at both ends is half that of the pipe open at one end and closed at the other.
(d) There is no simple relationship between the fundamental frequencies of the two pipes

Back 79

(b) The fundamental frequency of the pipe open at both ends is twice that of the pipe open

Front 80

A standing wave doesn't travel, it just oscillates. Does this contradict the definition of a
wave as a traveling disturbance?
(a) Yes. Since it doesn't travel it isn't really a wave.
(b) Yes. The definition needs to be modified to include waves that don't travel.
(c) No. The definition is wrong. Not all waves are traveling disturbances.
(d) No. A standing wave is produced by the interference of two traveling waves.

Back 80

(d) No. A standing wave is produced by the interference of two traveling waves.

Front 81

A string of length L is fixed at both ends and vibrates in its fundamental mode (first harmonic). Which of the following statements are true? (Check all that apply.)
(a) The wavelength is equal to L.
(b) The wavelength is equal to 2L.
(c) The ends of the strings are nodes.
(d) The center of the string is a node.

Back 81

(b) The wavelength is equal to 2L.
(c) The ends of the strings are nodes.

Front 82

Why does the pitch of a string fixed at both ends increase
when the tension in the string increases?
(a) The speed of waves on the string is greater so the frequency and pitch increase.
(b) The wavelength of waves on the string decreases so the frequency and pitch increase.
(c) The speed of waves on the string is greater so the wavelength and pitch increase.
(d) The wavelength of waves on the string increases so the frequency and pitch increase

Back 82

(a) The speed of waves on the string is greater so the frequency and pitch increase.

Front 83

Which of the following statements are true about sound? (Check all that apply.)
(a) Sound waves can travel though a vacuum.
(b) Sound waves in fluids are longitudinal.
(c) The pitch of a sound depends mainly on its frequency.
(d) The loudness of a sound depends only on its intensity.
(e) The speed of sound in air depends on the temperature of the air.
(f) The frequency of a sound wave is the same as the frequency of its source.

Back 83

(b) Sound waves in fluids are longitudinal.
(c) The pitch of a sound depends mainly on its frequency.
(e) The speed of sound in air depends on the temperature of the air.
(f) The frequency of a sound wave is the same as the frequency of its source.

Front 84

A. the length of one complete wave
B. what happens when two waves are in the same place at the same time
C. a traveling disturbance
D. a wave in which the disturbance of the medium is parallel to the direction of motion of the wave
E. a wave in which the disturbance of the
medium is perpendicular to the direction of motion of the wave
F. a wave that repeats itself in both time and space

Back 84

A. wavelength
B. interference
C. wave
D. longitudinal wave
E. transverse wave
F. periodic wave

Front 85

The period of oscillation of a simple pendulum depends on what factors?
(Check all that apply.)
(a) The length of the pendulum.
(b) The mass of the pendulum bob.
(c) The acceleration due to gravity.
(d) The amplitude of vibration.

Back 85

(a) The length of the pendulum.
(c) The acceleration due to gravity.
(d) The amplitude of vibration.

Front 86

Which of the following best describes the motion of a mass on a spring with a small amount of damping.
(a) There are no oscillations; the mass quickly comes to rest.
(b) There are a few oscillations; the mass quickly comes to rest.
(c) Each oscillation of the mass has slightly smaller amplitude; the mass comes to rest after many oscillations.
(d) The mass moves with simple harmonic motion.

Back 86

(c) Each oscillation of the mass has slightly smaller amplitude; the mass comes to rest after many oscillations.

Front 87

Which of the following are necessary for resonance in an oscillating system?
(Check all that apply.)
(a) A natural frequency of vibration.
(b) An external oscillator driving the system at any frequency.
(c) An external oscillator driving the system at a frequency close to the natural frequency.
(d) No damping

Back 87

(c) An external oscillator driving the system at a frequency close to the natural frequency.

Front 88

A 2.0 kg mass slides on a frictionless surface and is attached to an ideal spring with a spring sti!ness constant of 800 N/m. The mass is displaced a distance of 10 cm from its equilibrium position and released from rest. Neglect air resistance. Which of the following statements are true about the mass-spring system? (Check all that apply.)
(a) The motion is periodic.
(b) The mass moves with simple harmonic motion.
(c) The spring exerts a linear restoring force on the mass.
(d) The amplitude of the motion is 10 cm.
(e) The frequency of the motion is 10/π Hz.
(f) The potential energy of the mass is maximum when it passes the equilibrium position.

Back 88

(a) The motion is periodic.
(b) The mass moves with simple harmonic motion.
(c) The spring exerts a linear restoring force on the mass.
(d) The amplitude of the motion is 10 cm.
(e) The frequency of the motion is 10/π Hz.

Front 89

A transverse wave is
(a) a wave that repeats itself in both time and space.
(b) produced by the interference of incident and reflected waves.
(c) any traveling disturbance.
(d) a traveling disturbance where the disturbance of the medium is parallel to the direction of motion of the wave.
(e) a traveling disturbance where the disturbance of the medium is perpendicular to the direction of motion of the wave.

Back 89

(e) a traveling disturbance where the disturbance of the medium is perpendicular to the direction of motion of the wave.

Front 90

A mass slides on a frictionless surface and is attached to an ideal spring. The mass is displaced 15 cm from its equilibrium position and released from rest. The mass
(a) moves with simple harmonic motion.
(b) has an amplitude of 15 cm.
(c) has its maximum kinetic energy when it passes the equilibrium position.
(d) Both (a) and (b).
(e) All of the above.

Back 90

(e) All of the above.

Front 91

What are the boundary conditions for a pipe open at both ends?
(a) The ends are pressure nodes.
(b) The ends are displacement antinodes.
(c) The ends are displacement nodes.
(d) Both (a) and (b).
(e) Both (a) and (c).

Back 91

(d) Both (a) and (b).

Front 92

The frequency of oscillation of a simple pendulum depends on
(a) the length of the pendulum.
(b) the acceleration due to gravity.
(c) the mass of the pendulum bob.
(d) Both (a) and (b).
(e) All of the above.

Back 92

(d) Both (a) and (b).

Front 93

Unpolarized light is incident on a sheet of Polaroid with its polarization axis vertical. A second sheet of Polaroid with its polarization axis horizontal is placed a short distance from the first sheet so that any light that passes through the first sheet is incident on the second sheet. Which of the following best describes the light coming through the sheets?
(a) The light is vertically polarized after passing through the first sheet and horizontally polarized after passing through the second sheet.
(b) The light is vertically polarized after passing through the first sheet and remains vertically polarized after passing through the second sheet.
(c) The light is vertically polarized after passing through the first sheet. No light passes through the second sheet.
(d) No light passes through either sheet.

Back 93

(c) The light is vertically polarized after passing through the first sheet. No light passes through the second sheet.

Front 94

Unpolarized light is incident on a sheet of Polaroid with its polarization axis vertical. A second sheet of Polaroid with its polarization axis at 45° is placed a short distance from the first sheet so that any light that passes through the first sheet is incident on the second sheet. A third sheet of Polaroid with its polarization axis horizontal is placed a short distance from the second sheet so that any light that passes through the second sheet is incident on the third sheet. Which of the following best describes the light coming through the sheets?
(a) The light is vertically polarized after passing through the first sheet and horizontally polarized after passing through the third sheet.
(b) The light is vertically polarized after passing through the first sheet. Some light passes through the second sheet. No light passes through the third sheet.
(c) The light is vertically polarized after passing through the first sheet. No light passes through the second or third sheets.
(d) No light passes through any of the sheets.

Back 94

(a) The light is vertically polarized after passing through the first sheet and horizontally polarized after passing through the third sheet.

Front 95

In thin film interference what is it that interferes?
(a) the film
(b) the incident ray of light and the ray of light reflected from the front surface of the film
(c) the incident ray of light and the ray of light reflected from the back surface of the film
(d) the ray of light reflected from the front surface of the film and the ray of light reflected from the back surface of the film

Back 95

(d) the ray of light reflected from the front surface of the film and the ray of light reflected from the back surface of the film

Front 96

When is there a phase shift of 180° (π radians) on reflection of a ray of light?
(a) Always
(b) When the incident ray is in a material with a lower index of refraction than the material it is reflecting from.
(c) When the incident ray is in a material with a higher index of refraction than the material it is reflecting from.
(d) never

Back 96

(b) When the incident ray is in a material with a lower index of refraction than the material it is reflecting from.

Front 97

When blue light shines on a thin film the film appears dark. It appears bright when yellow light shines on it. Which of the following statements are true?
(Check all that apply.)
(a) There is a phase shift on reflection for the blue light but not for the yellow light.
(b) There is a phase shift on reflection for the yellow light but not for the blue light.
(c) The blue light undergoes constructive interference.
(d) The yellow light undergoes constructive interference.
(e) The blue light undergoes destructive interference.

Back 97

(d) The yellow light undergoes constructive interference.
(e) The blue light undergoes destructive interference.

Front 98

Which of the following can be explained by the wave theory of light?
(Check all that apply.)
(a) blackbody radiation
(b) diffraction
(c) dispersion
(d) double slit interference
(e) the law of refraction
(f) the photoelectric effect

Back 98

(b) diffraction
(c) dispersion
(d) double slit interference
(e) the law of refraction

Front 99

Which of the following are interference phenomena? (Check all that apply.)
(a) dispersion
(b) double slit interference
(c) single slit diffraction
(d) refraction

Back 99

(b) double slit interference
(c) single slit diffraction

Front 100

A ray of light in air is incident on a plate of glass at an angle to the normal. Which of the following statements are true? (Check all that apply.)
(a) There is a reflected ray.
(b) There is a refracted ray.
(c) The angle of reflection equals the angle of incidence.
(d) The angle of refraction equals the angle of incidence.
(e) The refracted ray bends toward the normal.
(f) The refracted ray bends away from the normal.
(g) The light appears to travels slower in the glass than in the air.
(h) The light appears to travel faster in the glass than in the air.

Back 100

(a) There is a reflected ray.
(b) There is a refracted ray.
(c) The angle of reflection equals the angle of incidence.
(e) The refracted ray bends toward the normal.
(g) The light appears to travels slower in the glass than in the air.

Front 101

Which of the following describe the image formed by a concave mirror when the object is beyond the center of curvature? (Check all that apply.)
(a) real
(b) virtual
(c) upright
(d) inverted
(e) magnified
(f) diminished
(h) the same size as the object

Back 101

(a) real
(d) inverted
(f) diminished

Front 102

Which of the following describe the image formed by a concave mirror when the object is within the focal point? (Check all that apply.)
(a) real
(b) virtual
(c) upright
(d) inverted
(e) magnified
(f) diminished
(h) the same size as the object

Back 102

(b) virtual
(c) upright
(e) magnified

Front 103

Which of the following describe the image formed by a convex mirror? (Check all that apply)
(a) real
(b) virtual
(c) upright
(d) inverted
(e) magnified
(f) diminished
(h) the same size as the object

Back 103

(b) virtual
(c) upright
(f) diminished

Front 104

Damped Harmonic Motion

Back 104

The amplitude of any real oscillating spring or swinging pendulum will slowly decrease in time until the oscillations stop altogether. The damping is generally due to the resistance of air and to internal friction within the oscillating system. The energy that is dissipated to thermal energy results in a decreased amplitude of oscillation

Front 105

Critical Damping

Back 105

Equilibrium is reached in the shortest time possible

Front 106

Resonant Frequency

Back 106

The natural vibrating frequency f₀ of a system

Front 107

WAVE VS PARTICLE VELOCITY
Is the velocity of a wave moving along a cord the same as the velocity of a particle of the cord?

Back 107

No. The two velocities are different, both in magnitude and direction. The wave on a rope moves to the right along the tabletop, but each piece of the rope only vibrates to and fro. (The rope clearly does not travel in the direction that the crest does)

Front 108

Longitudinal wave

Back 108

The vibration of particles of the medium is ALONG the direction of the wave's motion. These waves are readily formed on a stretched spring or Slinky by alternately compressing and expanding one end. The compressions are those areas where the coils are momentarily close together. Expansions are regions where the coils are momentarily far apart

Front 109

Transverse wave

Back 109

When a wave travels down a rope--say, from left to right--the particles of the rope vibrate up and down in a direction transverse (perpendicular) to the motion of the wave itself

Front 110

CELL PHONES
Cellular phones operate by radio waves with frequencies of about 1 or 2 GHz. These waves cannot penetrate objects that conduct electricity, such as a tree trunk or a sheet of metal. The connection is best if the transmitting antenna is within clear view of the handset. Yet it is possible to carry on a phone conversation even if the tower is blocked by trees, or if the handset is inside a car. Why?

Back 110

If the radio waves have a frequency of about 2 GHz, and the speed of propagation is equal to the speed of light, then the wavelength is about 0.15 m. The waves can diffract readily around objects 15 cm in diameter or smaller.

Front 111

DISTANCE FROM A LIGHTENING STRIKE
A rule of thumb that tells how close lightening has hit is, "one mile for every 5 seconds before the thunder is heard." Justify, noting that the speed of light is so high that the time for light to travel is negligible compared to the time for sound

Back 111

The speed of sound in air is about 340 m/s, so to travel 1 km = 1000 m takes about 3 seconds. One mile is about 1.6 kilometers, so the time for the thunder to travel a mile is about 5 seconds

Front 112

Loudness

Back 112

related to intensity

Front 113

Pitch

Back 113

For a sound refers to whether it is high or low. he physical quantity that determines pitch is the frequency. The lower the frequency, the lower the pitch

Front 114

The Law of Reflection

Back 114

the angle of incidence equals the angle of reflection

Front 115

Huygens' principle

Back 115

Every point on a wave front can be considered as a source of tiny wavelets that spread out in the forward direction at the speed of the wave itself. The new wave front is the envelope of all the wavelets--that is, the tangent to all of them

Front 116

Diffraction

Back 116

Waves bend in behind an obstacle and the wave fronts are partially interrupted. This is what water waves do. The bending of waves behind obstacles into the "shadow region" is knows as diffraction. Since diffraction occurs for waves, but not for particles, it can serve as one means for distinguishing the nature of light.

Front 117

CHANGING THE WAVELENGTH
(a) What happens to the interference pattern if the incident light (500 nm) is replaced by light of wavelength 700 nm?
(b) What happens instead if the wavelength stays at 500 nm but the slits are moved farther apart?

Back 117

(a) When λ decreases, but d stays the same, then the angle θ for bright fringes increases and the interference pattern spreads out. (b) Increasing the slit spacing d reduces θ for each order, so the lines are closer together

Front 118

A square is cut out of a copper sheet. The square is heated uniformly. As a result, it turns into:
(a) a square with a larger area
(b) a square with a smaller area
(c) a rectangle with a larger area
(d) a rectangle with a smaller area

Back 118

(a) a square with a larger area

Since all dimensions change by the same ratio, the square retains its shape. The area increases, and so does the thickness of the sheet.

Front 119

A square is cut out of a copper sheet. Two straight scratches on the surface of the square intersect forming an angle theta. The square is heated uniformly. As a result, the angle between the scratches
(a) increases
(b) decreases
(c) stays the same
(d) the answer depends on whether theta is an acute or obtuse angle

Back 119

(c) stays the same

Since all dimensions change by the same ratio, every "detail" of the square retains its shape. The scratches will extend in length, but they will still form the same angle.

Front 120

A square is cut out of a copper sheet. A circular hole is drilled in the square. The square is heated uniformly. As a result, the diameter of the hole
(a) increases
(b) decreases
(c) stays the same
(d) the answer depends on the size of the hole

Back 120

(a) increases

There is a popular misconception that the hole would get smaller because "the material around it expands." However, both experiment and logic dictate otherwise. One way to think about it is to imagine what would happen to the "disk" cut out of that hole. When heated, the disk would expand, of course, and so should "the empty space" left by the absence of that disk. Another way to visualize the expansion is to think of the material surrounding the hole as a large number of thin rings concentric with the hole itself. When heated, all of these rings would expand, including the innermost one, which "traces" the edge of the hole.

Front 121

The tank is heated until the pressure of the gas in the tank doubles. What is the temperature of the gas?
(a) 200 K
(b) 400 K
(c) 600 K
(d) 800 K

Back 121

(d) 800 K

Front 122

Having been heated to 800 K, at some point the tank starts to leak. By the time the leak is repaired, the tank contains only half as much gas, and the pressure of the remaining gas is again 1.00 atm. What is the temperature of the gas?
(a) 200 K
(b) 400 K
(c) 600 K
(d) 800 K

Back 122

(d) 800 K

Front 123

A diver named Jacques observes a bubble of air rising from the bottom of a lake (where the absolute pressure is 3.50 atm) to the surface (where the pressure is 1.00 atm). The temperature at the bottom is 4.0 ºC, and the temperature at the surface is 23.0 ºC.
Would it be safe for Jacques to hold his breath while ascending from the bottom of the lake to the surface?

Back 123

no
If Jacques were holding his breath, then air would be unable to enter or leave his lungs. As he ascends to the surface, the air in his lungs would expand, like the air in the bubble, and his lungs would have to stretch outward to hold this increased volume, which would be extremely unsafe.

In fact, even if he does not hold his breath, if he ascends too quickly after a particularly long or deep dive, the nitrogen dissolved in his bloodstream could form into small bubbles, which can be equally dangerous to any diver. This condition is known as decompression sickness, or more commonly as the bends.

Front 124

Refrigerator cooling

Back 124

In actuality, the idea that the refrigerator removes energy from the sample at a constant rate is a bit unrealistic. Warm objects lose energy more quickly than objects near the temperature of the freezer. This is described by Newton's law of cooling, discovered by Sir Isaac Newton.

Front 125

Which of the following statements are true?
(a) Steam burns the skin worse than hot water because the thermal conductivity of steam is much higher than that of liquid water.
(b) Steam burns the skin worse than hot water because the latent heat of vaporization is released as well.
(c) Hot water burns the skin worse than steam because the thermal conductivity of hot water is much higher than that of steam.
(d) Hot water and steam both burn skin about equally badly.

Back 125

(b) Steam burns the skin worse than hot water because the latent heat of vaporization is released as well.

The key point is that the latent heat of vaporization has to be taken into account for the steam.

Front 126

The quantity ∆Q/∆t is the rate of heat transfer from the hot to the cold end of the rod.

TRUE OR FALSE

Back 126

true

Front 127

The quantity ∆Q/∆t is the rate of heat added to the hot end of the rod to maintain its temperature.

TRUE OR FALSE

Back 127

true

Front 128

The quantity ∆Q/∆t is the rate of heat removed from the cold end of the rod to maintain its temperature

TRUE OR FALSE

Back 128

true

Front 129

The quantity ∆Q/∆t is the total amount of heat transferred from the hot to the cold end of the rod.

TRUE OR FALSE

Back 129

false

The flow of heat into, through, and out of the rod are equal under steady-state conditions in which the temperature of each end of the rod is constant. The heat conduction formula applies only in steady state; it does not apply to the situation in which one end of a bar is suddenly placed in a flame while the other end is held at fixed temperature (as in an ice bath); the formula would only apply after the temperature at every point in the bar had reached a steady-state value.

Front 130

If you wanted to find the area of the hot filament in a light bulb, you would have to know the temperature (determinable from the color of the light), the power input, the Stefan-Boltzmann constant, and what property of the filament?

(a) thermal radiation
(b) emissivity
(c) length

Back 130

(b) emissivity

Front 131

What is the primary mode of energy transfer from hot coffee inside a Thermos bottle to the environment?

Back 131

radiation

Front 132

What is the primary mode of energy transfer from your bare feet to a cold ceramic bathroom floor in the middle of winter?

Back 132

conduction

Front 133

What is the primary mode of energy transfer from your body to your hands when you blow on them to warm them?

Back 133

convection

Front 134

What is the primary mode of energy transfer into your sealed car parked in the sun on a hot summer day?

Back 134

radiation

Front 135

What is the primary mode of the flow of energy from your tongue to a metal railing if you happen to lick it on a cold winter day?

Back 135

conduction

Front 136

What is the primary mode of energy transfer from a hair dryer to your wet hair?

Back 136

convection

Front 137

What is the primary mode of energy transfer from your body on a cold day with no wind?

Back 137

radiation

Front 138

What is the primary mode of energy transfer away from your body on a very windy day?

Back 138

convection

Front 139

An ideal gas expands through an adiabatic process. Which of the following statements is/are true?
Check all that apply.
(a) The work done by the gas is negative, and heat must be added to the system.
(b) The work done by the gas is positive, and no heat exchange occurs.
(c) The internal energy of the system has increased.
(d) The internal energy of the system has decreased.

Back 139

(b) The work done by the gas is positive, and no heat exchange occurs.
(d) The internal energy of the system has decreased.

Front 140

After the adiabatic expansion described in the previous part, the system undergoes a compression that brings it back to its original state. Which of the following statements is/are true?
Check all that apply.
(a) The total change in internal energy of the system after the entire process of expansion and compression must be zero.
(b) The total change in internal energy of the system after the entire process of expansion and compression must be negative.
(c) The total change in temperature of the system after the entire process of expansion and compression must be positive.
(d) The total work done by the system must equal the amount of heat exchanged during the entire process of expansion and compression.

Back 140

(a) The total change in internal energy of the system after the entire process of expansion and compression must be zero.
(d) The total work done by the system must equal the amount of heat exchanged during the entire process of expansion and compression.

Front 141

If the period is doubled, the frequency is
(a) unchanged
(b) doubled
(c) halved

Back 141

(c) halved

Front 142

Which of the following statements best describes the characteristic of the restoring force in the spring-mass system described in the introduction?
(a) The restoring force is constant.
(b) The restoring force is directly proportional to the displacement of the block.
(c) The restoring force is proportional to the mass of the block.
(d) The restoring force is maximum when the block is in the equilibrium position.

Back 142

(b) The restoring force is directly proportional to the displacement of the block.

Whenever the oscillations are caused by a restoring force that is directly proportional to displacement, the resulting periodic motion is referred to as simple harmonic motion.

Front 143

What is the acceleration of a block when it passes through its equilibrium position

Back 143

0

Your results from Parts B and C show that the acceleration of the block is negative when the block has undergone a positive displacement. Then, the acceleration's magnitude decreases to zero as the block goes through its equilibrium position. What do you expect the block's acceleration will be when the block is to the left of its equilibrium position and has undergone a negative displacement?

Front 144

The magnitude of the block's acceleration reaches its maximum value when the block is

Back 144

at either its rightmost or leftmost position.

Front 145

The speed of the block is zero when it is

Back 145

at either its rightmost or leftmost position.

Front 146

The speed of the block reaches its maximum value when the block is

Back 146

in the equilibrium position.

Front 147

If the velocity of the wave remains constant, then as the frequency of the wave is increased, the wavelength

Back 147

decreases

Front 148

What is the relationship between ω and f?

Back 148

2πf

Front 149

An oscillator creates periodic waves on two strings made of the same material. The tension is the same in both strings.
If the strings have different thicknesses, which of the following parameters, if any, will be different in the two strings?
(a) wave frequency
(b) wave speed
(c) wavelength
(d) none of the above

Back 149

(b) wave speed
(c) wavelength

Front 150

An oscillator creates periodic waves on two strings made of the same material. The tension is the same in both strings.
(a) wave frequency
(b) wave speed
(c) wavelength
(d) none of the above

Back 150

(e) none of the above

In summary, when a wave travels along a string, the wave speed depends exclusively on the properties of the string, whereas the wave frequency is set by the oscillator that creates the waves. The wavelength is a quantity that can vary if either the wave speed or the wave frequency is changed. Thus, it can be modified by changing either the motion of the oscillator or the properties of the string.

Front 151

What is a sound wave?
(a) Propagation of sound particles that are different from the particles that comprise the medium
(b) Propagation of energy that does not require a medium
(c) Propagation of pressure fluctuations in a medium
(d) Propagation of energy that passes through empty spaces between the particles that comprise the medium

Back 151

(c) Propagation of pressure fluctuations in a medium

Front 152

Does air play a role in the propagation of the human voice from one end of a lecture hall to the other?

Back 152

yes

Front 153

A certain sound is recorded by a microphone. The same microphone then detects a second sound, which is identical to the first one except that the amplitude of the pressure fluctuations is larger. In addition to the larger amplitude, what distinguishes the second sound from the first one?
(a) It is perceived as higher in pitch.
(b) It is perceived as louder.
(c) It has a higher frequency.
(d) It has a longer wavelength.

Back 153

(b) It is perceived as louder

Front 154

A certain sound is recorded by a microphone. A second sound that has twice the frequency is detected by the same microphone. In addition to the higher frequency, what distinguishes the second sound from the first one?
(a) It is perceived as higher in pitch.
(b) It is perceived as louder.
(c) It has a higher amplitude.
(d) It has a longer wavelength.

Back 154

(a) It is perceived as higher in pitch

When we double the frequency of a sound wave, we produce a sound that is said to be an octave above the first.

Front 155

What varies between two tones that are different in timbre, that is, two tones that have the same fundamental frequency but are produced, say, by different musical instruments?
(a) the pitch
(b) the harmonic content
(c) nothing

Back 155

(b) the harmonic content

Front 156

If the period of the oscillator doubles, what happens to the wavelength and wave speed?
(a) The wavelength is halved but the wave speed is unchanged.
(b) The wavelength is unchanged but the wave speed doubles.
(c) The wavelength doubles but the wave speed is unchanged.

Back 156

(c) The wavelength doubles but the wave speed is unchanged

Front 157

If the amplitude of the oscillator doubles, what happens to the wavelength and wave speed?
(a) The wavelength is unchanged but the wave speed doubles.
(b) The wavelength doubles but the wave speed is unchanged.
(c) Both wavelength and wave speed are unchanged.

Back 157

(c) Both wavelength and wave speed are unchanged

As you have discovered, when waves travel along a string, the wave speed remains unchanged, unless the properties of the string are changed. The wavelength can be varied only by changing the frequency, or alternatively the period, of the oscillator that creates the waves.

Front 158

A certain sound contains the following frequencies: 400 Hz, 1600 Hz, and 2400 Hz. Select the best description of the sound.

(a) This is a pure tone.
(b) This is a complex tone with a fundamental of 400 Hz, plus some of its overtones.
(c) This is a complex tone with a virtual pitch of 800 Hz.
(d) These frequencies are unrelated, so they are probably pure tones from three different sound sources.

Back 158

(b) This is a complex tone with a fundamental of 400 Hz, plus some of its overtones.