Cairo: Mosby’s Respiratory Care Equipment, 8th Edition
CHAPTER 01: Basic Physics for the Respiratory Therapist
Test Bank
MULTIPLE CHOICE
1.	Power is a measure of which of the following?
a.	Mechanical energy	
b.	Gravitational potential energy	
c.	The rate at which work is being performed	
d.	The rate at which atoms and molecules move	

ANS:	C
Power is a measure of the rate at which work is being performed. The formula P = W/J, where W = watts and 1 W is equal to 1 J/s, expresses this. Joules are the international standard for expressing energy and work.

REF:	Page 2

2.	When effort produces a change in the position of matter:
a.	work is performed.	
b.	it is known as a joule.	
c.	mechanical power is created.	
d.	the law of the conservation of energy is being used.	

ANS:	A
Work is performed only when effort or outside forces produce a change in the position of matter.

REF:	Page 3

3.	The unit used to express the force of 1 N acting on a 1-kg object to move it 1 m is which of the following?
a.	Watt	
b.	Joule	
c.	Kilowatt	
d.	Kinetic energy	

ANS:	B
One Joule is equal to the force of 1 N acting on 1 kg. A watt is equivalent to 1 J/s. A kilowatt is simply 1000 W. Kinetic energy is energy an object possesses when it is in motion.

REF:	Page 2

4.	Power is expressed in which of the following units?
a.	Newtons	
b.	Joules	
c.	Ohms	
d.	Watts	

ANS:	D
Power is a measure of the rate at which work is being performed. Energy and work are measured in joules. One joule is the force of 1 N acting on a 1-kg object to move it 1 m. Ohms is the resistance an electrical circuit possesses.

REF:	Page 2

5.	Four horsepower is equal to how many kilowatts?
a.	5.36	
b.	2.98	
c.	2984	
d.	186.5	

ANS:	B
1 hp = 0.746 kW.
1 hp/0.746 = 4 hp/X.
X = 4 ´ 0.476 = 2.98 kW.

REF:	Page 2

6.	The energy that an object possesses when it is in motion is called:
a.	Sound	
b.	Kinetic	
c.	Thermal	
d.	Potential	

ANS:	B
Kinetic energy is the energy an object possesses when it stays in motion. Potential energy is stored energy, and it exists in many forms such as thermal energy or sound waves.

REF:	Page 3

7.	If the velocity of an object is reduced by half, its kinetic energy will be which of the following?
a.	Reduced to one eighth	
b.	Increased twofold	
c.	Reduced twofold	
d.	Not changed	

ANS:	A
Kinetic energy = 1/2 (mass of object ´ square of velocity it is traveling, or mv2) or KE = 1/2 (V ´ V). If the velocity is reduced by half, then KE = 1/2 (1/2V ´ 1/2V), or 1/2 (1/4) = 1/8 reduction.

REF:	Page 3

8.	Energy that is stored in an object is called which of the following?
a.	Kinetic	
b.	Potential	
c.	Chemical	
d.	Mechanical	

ANS:	B
Energy that is stored or possessed by an object because of its position is called potential energy. Mechanical energy can be divided into either kinetic energy (KE) or potential energy. Chemical potential energy often refers to the bonds in petroleum oils that, if broken, can be converted to KE.

REF:	Page 3

9.	The potential energy of a compressed spring is known as which of the following?
a.	Gravitational	
b.	Chemical	
c.	Inelastic	
d.	Elastic	

ANS:	D
The potential energy (PE) stored in a compressed spring is called elastic potential energy. This energy is released when the spring is allowed to uncoil. Gravitational PE is the energy an object possesses if it is held above any surface, energy that the object’s weight gains as it falls. Chemical PE resides in the chemical bonds of the atoms that make up the object. Inelastic PE would not apply once the spring is compressed.

REF:	Page 3

10.	The energy stored in heating oil is known as which of the following?
a.	Elastic	
b.	Atomic	
c.	Chemical	
d.	Gravitational	

ANS:	C
Petroleum reserves of coal, oil, and gas represent chemical PE by virtue of the chemical bond that must be broken to release energy. Heating oil PE has chemical-to-chemical bonds. Atomic energy involves two processes—fission (splitting atoms) and fusion (joining two atoms).

REF:	Page 3

11.	The kinetic theory holds that:
a.	All matter is composed of tiny particles.	
b.	Elements combine in fixed proportions to form molecules.	
c.	The energy that an object gains as it falls is a result of gravity.	
d.	Atoms and molecules that make up matter are in constant motion.	

ANS:	D
KE is the energy an object possesses while in motion.

REF:	Page 3

12.	Which is the correct order for increasing size?
a.	Atoms, molecules, mixtures, compounds, elements	
b.	Atoms, elements, molecules, compounds, mixtures	
c.	Elements, atoms, molecules, compounds, mixtures	
d.	Atoms, elements, mixtures, molecules, compounds	

ANS:	B
All matter, whether in gas, liquid, or solid form, is made up of atoms that can combine to form elements; the elements can then combine to form molecules. Molecules can combine to form compounds. Combining compounds makes a mixture.

REF:	Page 3

13.	Atoms and molecules arranged in an orderly fashion are called:
a.	Solids	
b.	Mixtures	
c.	Crystalline	
d.	Amorphous	

ANS:	C
Crystalline solids are highly organized structures whose atoms and molecules are arranged in a lattice configuration. Amorphous solids have atoms and molecules that are less rigidly arranged.

REF:	Page 3

14.	The most potential energy is contained by which state of matter?
a.	Gases	
b.	Solids	
c.	Liquids	
d.	Mixtures	

ANS:	B
Of all states of matter, solids contain the most potential energy; solids are followed by liquids, then gases.

REF:	Page 3

15.	Which of the following are amorphous solids?
I. Iron
II. Glass
III. Plastic
IV. Margarine
a.	I 	
b.	I and III 	
c.	II and IV 	
d.	II, III, and IV 	

ANS:	D
Glass and margarine are always considered amorphous solids. Plastic usually shows flexibility, which implies that it has amorphous features, so it should be considered amorphous. Iron, however, has well-organized atoms in a crystalline arrangement.

REF:	Page 3

16.	Supercooled liquids are also known as which of the following?
a.	Elements	
b.	Compounds	
c.	Crystalline solids	
d.	Amorphous solids	

ANS:	D
Amorphous solids are sometimes called supercooled liquids. Elements and compounds alone can combine to form either crystalline or amorphous solids.

REF:	Page 3

17.	The least amount of kinetic energy is possessed by which one of the following?
a.	Air	
b.	Iron	
c.	Water	
d.	Plastic	

ANS:	B
Of the three states of matter, solids possess the least amount of KE. The bonds holding their atoms together limit the mobility of the particles that make up the solid.

REF:	Page 3

18.	Incompressible substances that are able to maintain their volume and shape are called:
a.	Gases	
b.	Solids	
c.	Liquids	
d.	Compounds	

ANS:	B
Solids are characterized as incompressible substances that can maintain their volume and shape. Gases and liquids do not maintain their volume and shape as well as solids do.

REF:	Page 3

19.	The weakest cohesive forces between constituent particles are present in which of the following?
a.	Water	
b.	Plastic	
c.	Hydrogen	
d.	Liquid oxygen	

ANS:	C
Gases have extremely weak or no cohesive forces between their atoms. Hydrogen is the only gas among the four choices.

REF:	Page 3

20.	The interconversions of solids, liquids, and gases can be accomplished by which of the following?
I. Altering the relationship between KE and PE
II. Removing heat from a substance
III. Using Archimedes’s principle
IV. Using the Coanda effect
a.	I 	
b.	I and II 	
c.	III and IV 	
d.	II, III, and IV 	

ANS:	B
The change of state from solid to liquid to gas is a process known as interconversion that is accomplished by changing relationships between KE and PE. One example of making this kind of change can be done by removing heat from a substance. Archimedes’ principle involves buoyancy, and the Coanda effect involves movement of liquids and gases through tubes.

REF:	Page 4

21.	The temperature at which a solid converts to a liquid is the _____ point.
a.	Freezing 	
b.	Melting 	
c.	Boiling 	
d.	Critical 	

ANS:	B
This is the definition of melting point. Freezing is the change of a substance from a liquid to a solid. Melting is the change from a solid to a liquid. The temperature at which a liquid converts to a gaseous state is the boiling point. The critical point is used to describe the critical temperature and critical pressure of a substance.

REF:	Page 4

22.	Which of the following statements are true concerning the latent heat of fusion?
I. It is also called evaporation.
II. It is expressed in calories per gram.
III. It will cause a complete change of state.
IV. It is expressed in grams per degree Celsius.
a.	I and II 	
b.	I and III 	
c.	II and III 	
d.	II, III, and IV 	

ANS:	C
Latent heat of fusion is the amount of heat, in calories, that must be added to cause a complete change of state. Evaporation is change from liquid to gas. Latent heat is expressed as calories per gram. Evaporation is the passive change of state over time, with no addition of heat.

REF:	Page 4

23.	The process whereby a solid directly becomes a gas is known as:
a.	Latent heat	
b.	Sublimation	
c.	Evaporation	
d.	Condensation	

ANS:	B
The direct change of state from solid to gas is called sublimation. Evaporation involves change from liquid to gas. Latent heat involves a change of state in matter of any form.

REF:	Page 4

24.	Which two of the following are ways to enhance the process of evaporation?
I. Decrease the temperature of the liquid
II. Increase the temperature of the liquid
III. Decrease atmospheric pressure
IV. Increase atmospheric pressure
a.	I and III 	
b.	I and IV 	
c.	II and III 	
d.	II and IV 	

ANS:	C
Either decreasing the temperature or increasing the atmospheric pressure will decrease the evaporation rate.

REF:	Page 5

25.	How much pressure must be applied to maintain equilibrium between liquid and gaseous oxygen at its critical temperature?
a.	1 atm	
b.	37 atm	
c.	43.9 atm	
d.	49.7 atm	

ANS:	D
When the atmospheric pressure is maintained at 49.7 atm, at a temperature of –119° C (oxygen’s critical temperature) oxygen maintains an equal balance between its liquid and gaseous states.

REF:	Page 6

26.	The point at which the vapor pressure of a liquid equals atmospheric pressure is known as:
a.	Critical temperature	
b.	Vapor pressure	
c.	Boiling point	
d.	Latent heat	

ANS:	C
The boiling point is the temperature at which the vapor pressure of a liquid equals atmospheric pressure. Critical temperature is the temperature above which gases cannot convert back to liquid. Critical pressure is the amount of pressure applied at the critical temperature to maintain balance between the liquid and gas phases.

REF:	Page 5

27.	The temperature above which gas molecules cannot be converted back to a liquid, no matter how much pressure is exerted, is known as which of the following?
a.	Critical temperature	
b.	Critical point	
c.	Boiling point	
d.	Latent heat	

ANS:	A
This is the definition of critical temperature.

REF:	Page 6

28.	The boiling point of liquid oxygen is which of the following?
a.	–119° C	
b.	182° F	
c.	–183° C	
d.	49.7° C	

ANS:	C
This is the boiling point of liquid oxygen.

REF:	Page 6

29.	Which two of the following are considered vapors?
I. Carbon dioxide
II. Nitrogen
III. Oxygen
IV. Water
a.	I and III 	
b.	I and IV 	
c.	II and III 	
d.	II and IV 	

ANS:	B
A vapor is the gaseous form of any substance that can exist as a solid or a liquid at ordinary temperature and pressures. Water and dry ice (CO2) can exist as a liquid or a solid at room temperature; N2 and O2 cannot.

REF:	Page 7
30.	How many degrees Fahrenheit is 200° K?
a.	–99.4	
b.	–58.3	
c.	32	
d.	0	

ANS:	A
Use the formula in Box 1-3 to calculate this conversion.

REF:	Page 9, Box 1-3	

31.	Absolute zero is which of the following?
a.	0° K	
b.	The freezing point of water	
c.	Routinely measured in Fahrenheit	
d.	The temperature at which all molecular motion stops	

ANS:	A
On the Kelvin scale, 0° K is absolute zero.

REF:	Page 9, Box 1-3	

32.	20° C equals how many Kelvin?
a.	32	
b.	68	
c.	253	
d.	293	

ANS:	D
See Figure 1-3 in the textbook.

REF:	Page 9, Box 1-3	

33.	How many degrees Celsius is 373° K?
a.	32	
b.	100	
c.	273	
d.	341	

ANS:	B
See Box 1-3.

REF:	Page 9, Box 1-3	

34.	How many degrees Fahrenheit is 100° K?
a.	–331	
b.	–279	
c.	–173	
d.	212	

ANS:	B
See Box 1-3.

REF:	Page 9, Box 1-3	

35.	How many degrees Fahrenheit is 425° K?
a.	152	
b.	274	
c.	306	
d.	698	

ANS:	C
See Box 1-3.

REF:	Page 9, Box 1-3	

36.	Which two of the following temperatures are not equal?
I. 15° C = 288° K
II. 98.6° C = 32° F
III. 20° F = –6.7° C
IV. 100° C = 273° K
a.	II and IV 	
b.	I and III 	
c.	III and IV 	
d.	I and II 	

ANS:	A
See Box 1-3.

REF:	Page 9, Box 1-3	

37.	How many degrees Celsius is 101° F?
a.	24	
b.	145	
c.	38.3	
d.	56.1	

ANS:	C
See Box 1-3.

REF:	Page 9, Box 1-3	

38.	How many degrees Kelvin is 25° F?
a.	298	
b.	277	
c.	269	
d.	266	

ANS:	C
See Box 1-3.

REF:	Page 9, Box 1-3	

39.	How many mm Hg is 25 cm H2O?
a.	2.45	
b.	18.4	
c.	188	
d.	34	

ANS:	B
See Box 1-4.

REF:	Page 9, Box 1-3	

40.	How many kilopascals are equal to 15 mm Hg?
a.	2	
b.	11	
c.	153	
d.	1.47	

ANS:	A
See Box 1-4.

REF:	Page 9, Box 1-4	

41.	A reduction in the force of gravity will cause the atmospheric pressure to:
a.	Shift	
b.	Increase	
c.	Decrease	
d.	Remain constant	

ANS:	C
Atmospheric pressure is highest at sea level. An increase in altitude will cause atmospheric pressure to decrease, which leads to a decrease in the force of gravity.

REF:	Page 9

42.	What are the two opposing forces in a mercury barometer?
a.	The weight of the mercury column and the force of the gas molecules	
b.	The weight of the mercury column and the spring tension	
c.	Spring tension and gas pressure	
d.	Gravity and gas pressure	

ANS:	A
In a mercury barometer the weight of a column of mercury must equilibrate with the force of gas molecules.

REF:	Page 9

43.	The effects of buoyancy are best explained by:
a.	Archimedes’s principle	
b.	Bernoulli principle	
c.	Dalton’s law	
d.	Boyle’s law	

ANS:	A
Buoyancy occurs when an object is submerged in water. The object feels lighter than it is above water. The Bernoulli principle, Dalton’s law, and Boyle’s law relate to how gases or fluids vary with changes in pressure, volume, or temperature.

REF:	Page 10

44.	Specific gravity is best described as which of the following?
I. A measure of density
II. An application of Archimedes’s principle
III. A measurement that can be performed on liquids only
a.	I 	
b.	I and II 	
c.	II and III 	
d.	I, II, and III 	

ANS:	B
Specific gravity calculations use Archimedes’s principle in comparing a substance’s weight and density relative to a standard. The measurement of specific gravity can also be applied to gases.

REF:	Page 10

45.	Properties of a viscous liquid are:
I. Increased cohesive forces between its molecules
II. Low density
III. High density
IV. Free flow
a.	I and III 	
b.	I, II, and IV 	
c.	II and IV 	
d.	III and IV 	

ANS:	A
Viscosity is influenced by the strength of the cohesive forces between the molecules and an object’s density.

REF:	Page 11

46.	Which of the following is least viscous?
a.	Plastic	
b.	Gelatin (e.g., Jell-O™)	
c.	Metal	
d.	Glass	

ANS:	B
Plastic, metal, and glass have cohesive forces between the molecules that are strong enough to prevent any movement under normal circumstances. Jell-O’s viscosity will increase with low temperatures and decrease as temperature rises.

REF:	Page 11

47.	Forces that cause water to be absorbed by a paper towel are called _____ forces.
a.	van der Waals 	
b.	Adhesive 	
c.	Cohesive 	
d.	Surface 	

ANS:	B
The adhesive forces between the molecules of the paper towel and the water are stronger than the attractive cohesive forces the water molecules have for each other.

REF:	Page 11

48.	A hydrometer is usually associated with measuring which of the following?
I. Hydrogen content
II. Specific gravity
III. Weight density
IV. Water vapor
a.	I and III 	
b.	II and IV 	
c.	II and III 	
d.	I, II, and III 	

ANS:	C
Hydrometers are used to measure the weight density or specific gravity of liquids.

REF:	Page 10

49.	Viscosity has an influence on which of the following?
I. Laminar flow
II. Fluid mechanics
III. Sedimentary rate
IV. Streamlined flow
a.	I 	
b.	II and III 	
c.	II and IV 	
d.	I, II, and IV 	

ANS:	D
Viscosity is an important factor to consider in conjunction with laminar flow, streamlined flow, and fluid mechanics.

REF:	Page 11

50.	Forces at the molecular interface between oil and water are known as _____ forces.
a.	van der Waals 	
b.	Hydrostatic 	
c.	Cohesive 	
d.	Adhesive 	

ANS:	C
Surface tension is generated by the cohesive forces of molecules at a gas-liquid interface or at the interface of two immiscible liquids such as oil and water. Adhesive forces are attractive forces between two different kinds of molecules, and van der Waals forces are physical intermolecular forces that cause molecules to be attracted to each other.

REF:	Page 11

51.	Surface tension is present in a container with which of the following?
a.	Oxygen and hydrogen	
b.	Water and mercury	
c.	Water and chlorine	
d.	Water and salt	

ANS:	B
When water and mercury are mixed together, they will separate into two distinct liquids because of surface tension. Oxygen and hydrogen will combine to form water. Both salt and chlorine will dissolve in water easily.

REF:	Page 11

52.	A small-diameter glass tube is placed upright in a container of mercury. The meniscus at the top of the column of mercury is convex. This demonstrates that the:
a.	Cohesive forces of mercury are weak.	
b.	Cohesive forces of mercury are strong.	
c.	Adhesive forces within the mercury are strong.	
d.	Adhesive forces between the mercury and the glass are strong.	

ANS:	B
Cohesive forces within the mercury are stronger than the adhesive forces between the mercury and the glass. If the cohesive forces within the mercury were weaker than the adhesive forces, the meniscus would be concave. See Box 1-5.

REF:	Page 11

53.	According to the Système International d’Unités (SI), surface tension is measured in:
a.	cc3	
b.	lb/in2	
c.	lb/cc3	
d.	dyne/cm	

ANS:	D
In the SI system of measurements, surface tension is measured in dyne/cm.

REF:	Page 12

54.	Which substance has the lowest surface tension?
a.	Water at 20° C	
b.	Water at 37° C	
c.	Blood at 37° C	
d.	Ethyl alcohol at 20° C	

ANS:	D
See Table 1-3.

REF:	Page 12

55.	The surface tension of a liquid:
a.	Does not vary with temperature	
b.	Increases as temperatures increase	
c.	Increases as temperature decreases	
d.	Decreases as temperature increases	

ANS:	D
The surface tension of any given liquid varies inversely with its temperature. Adding heat to a liquid causes the molecules to move more vigorously and break the bonds that are holding them in liquid form.

REF:	Page 4

56.	According to Laplace’s law, if the surface tension of a sphere is doubled, what will happen to the pressure within a sphere?
a.	The pressure will decrease by one half.	
b.	The pressure will increase by one half.	
c.	The pressure will quadruple.	
d.	The pressure will double.	

ANS:	D
Laplace’s law, P = 2(ST/r), states that the pressure within a sphere is directly related to the surface tension of the liquid and inversely related to the radius of the sphere; that is, both surface tension and pressure within a sphere will change equally in the same proportion.

REF:	Page 12

57.	What will happen to the surface tension of water droplets when a surface-active agent is added?
a.	Nothing will happen.	
b.	It will increase.	
c.	It will decrease.	
d.	It will be eliminated.	

ANS:	C
Surface tension is the force exerted by like molecules at the liquid’s surface. The introduction of a surface-active agent (e.g., soap) would decrease the cohesive forces between the water droplets, thus reducing their surface tension at the surface. With liquids (e.g., water), surface tension can be made to increase or decrease, but it cannot be eliminated. See Figures 1-8, 1-9A, and 1-9B.

REF:	Pages 11 and 12	

58.	For measurements near the surface of the Earth, mass may be replaced by which of the following?
a.	Weight	
b.	Volume	
c.	Surface tension	
d.	Specific gravity	

ANS:	A
Density is defined as a substance’s mass per unit volume (d = mass/volume). Near the Earth’s surface, mass can be replaced by weight. Weight density (dw) = weight/volume. As one rises in altitude, the force of gravity decreases—as does the relationship between mass and weight (i.e., mass is constant, whereas weight decreases).

REF:	Page 10

59.	Which of the following shows the correct relationship among density, volume, and mass?
I. Density = volume/mass
II. Volume = density/mass
III. Mass = (density)  (volume)
IV. Weight density = weight/volume
a.	I and III 	
b.	I and IV 	
c.	IV 	
d.	III and IV 	

ANS:	D
Given density, d = mass (m)/volume (v), the equation can be solved for each variable: m = dv, v = m/d. When mass is substituted by weight, dw = w/v.

REF:	Page 10

60.	Under what conditions is the relationship between mass and weight constant?
a.	In outer space	
b.	At zero gravity	
c.	At the center of the Earth	
d.	Near the surface of the Earth	

ANS:	D
At the surface of the Earth, two equations apply: d = m/v, dw = w/v. In space and at zero gravity, weight is not a factor; at the Earth’s core, extreme gravitational forces would increase the weight as mass remained constant.

REF:	Page 10

61.	For solids and liquids, density can be expressed in which of the following units?
I. g/L
II. mg/mL
III. g/cc
IV. L/cc
a.	I 	
b.	II and III 	
c.	II and IV 	
d.	I, II, and III 	

ANS:	D
For solids and liquids, density = grams (g)/liter (L) or grams (g)/cubic centimeter cm3. Using d = g/L, divide both sides by 1000. Density can also be expressed in mg/mL.

REF:	Page 10

62.	Boyle’s law describes the relationship between which of the following?
a.	Pressure and temperature	
b.	Volume and temperature	
c.	Volume and pressure	
d.	Pressure and density	

ANS:	C
Boyle’s law states that at a constant temperature, the volume of a gas varies inversely proportional to pressure [V = 1/P]. The relationship between volume and temperature is expressed in Charles’ law. The relationship between pressure and temperature is described by Gay-Lussac’s law.

REF:	Page 13

63.	If temperature is constant, which pressure results in the largest volume?
a.	15 mm Hg	
b.	760 mm Hg	
c.	1520 mm Hg	
d.	2000 mm Hg	

ANS:	A
See Figure 1-10.

REF:	Page 13

64.	Which of the following formulas represents Boyle’s law?
a.	V = 2P	
b.	V = 1/2P	
c.	P1V1 = P2V2	
d.	P1/P2 = V1/V2	

ANS:	C
Boyle’s law can be expressed as a ratio: P1V1 = P2V2.

REF:	Page 13

65.	The relationship of how the volume of a gas varies with temperature is known as _____ law.
a.	Gay-Lussac’s 	
b.	Newton’s 	
c.	Charles’ 	
d.	Boyle’s 	

ANS:	C
The relationship between pressure and volume is described by Boyle’s law, between volume and temperature, by Charles’ law; between pressure and temperature, by Gay-Lussac’s law. Newton detailed the many relationships of gravitational force and motion.

REF:	Page 13

66.	Which of the following formulas represents Gay-Lussac’s law?
a.	P1/T1 = T2/P2	
b.	P1T1 = P2T2	
c.	P1T2 = P2T1	
d.	P = 1/T	

ANS:	C
Gay-Lussac expressed the relationship between pressure and temperature. If P/T = K (where K=constant), then P1/T1 = P2/T2.

REF:	Page 14

67.	Which gas law describes the relationship between the temperature and pressure of a gas when volume is constant?
a.	Gay-Lussac’s law	
b.	Charles’ law	
c.	Dalton’s law	
d.	Boyle’s law	

ANS:	A
Gay-Lussac expressed the relationship between pressure and temperature.

REF:	Page 14

68.	The direct relationship between the volume and temperature of a gas is the basic principle of _____ law.
a.	Gay-Lussac’s 	
b.	Charles’ 	
c.	Dalton’s 	
d.	Boyle’s 	

ANS:	B
Charles’ law is stated as follows: when the pressure of a gas is held constant, the volume of a gas varies directly with its absolute temperature, which is expressed in Kelvin.

REF:	Page 13

69.	It is implied that the absolute temperature of a gas will rise as the pressure is increased when which of the following occurs?
a.	Absolute temperature of the gas reaches absolute zero	
b.	Size of the container remains constant	
c.	Volume of the gas is held constant	
d.	Volume of the gas is increased	

ANS:	C
When the volume of a gas is constant, the temperature of the gas will rise as the pressure is increased (Gay-Lussac’s law). Absolute zero is a theoretical temperature that has never been reached. The size of the container does not vary directly with volume.

REF:	Page 14

70.	The combined-gas law best describes which of the following?
a.	The behavior of all gases when volume is constant	
b.	The combined behavior of pressure, volume, and temperature	
c.	The additive properties of individual gases occupying the same space	
d.	The macroscopic behavior of gases when any or all variables change simultaneously	

ANS:	D
The combined-gas law describes the macroscopic behavior of gases when any or all of the variables change simultaneously. As such, the combined-gas law states that the absolute pressure of a gas is inversely related to the volume it occupies and directly related to its absolute temperature, or PV/T = nR.

REF:	Page 14

71.	Which is (are) the correct formula(s) for the principles of the combined-gas law?
a.	P1V1/T1 = P2V2/T2	
b.	PVT = nR	
c.	P1V1/T2 = P2V2/T1	
d.	T2/P1V1 = T1/P2V2	

ANS:	A
That is the formula for the combined-gas law.

REF:	Page 14
72.	In the combined-gas law, n represents:
a.	Boltzmann’s Universal Gas Constant	
b.	The atomic mass of the gas	
c.	The number of moles of gas	
d.	The partial pressure of a gas	

ANS:	C
Boltzmann’s constant is represented as R. The combined-gas laws do not use the atomic mass or the partial pressure of any gas as a variable in any calculations presented in answers B and D.

REF:	Page 14

73.	The sum of the partial pressures of a gas mixture equals the total gas pressure of the system. This statement represents which of the following laws?
a.	Dalton’s law	
b.	Avogadro’s law	
c.	The-combined gas law	
d.	Boltzmann’s Universal Gas Constant	

ANS:	A
The partial pressure of a gas within a gas mixture can be calculated by multiplying the total pressure of the mixture by the percentage of the mixture it occupies. Avogadro’s law states that equal volumes of gas at the same pressure and temperature contain the same number of molecules. The combined-gas law does not involve partial pressures. Boltzmann’s Universal Gas Constant is part of the combined-gas law, where R is Boltzmann’s Universal Gas Constant, which refers to the absolute temperature and energy in a molecule of gas.

REF:	Page 14

74.	The partial pressure of a gas can be obtained by doing which of the following?
a.	Multiplying the total mixture pressure by the percentage a particular gas occupies	
b.	Multiplying the atmospheric pressure by the percentage of water vapor present	
c.	Subtracting the partial pressure of water vapor from the atmospheric pressure	
d.	Dividing the total pressure of a gas mixture by the atmospheric pressure	

ANS:	A
Dalton’s law states that the sum of the partial pressures of a gas mixture equals the total pressure of the system. Therefore, the partial pressure of a single gas may be calculated by multiplying the percentage of the gas in the gas mixture by the total pressure.

REF:	Page 14

75.	The partial pressure of nitrogen at 1 atm is _____ mm Hg.
a.	661.2 	
b.	592.8 	
c.	159.6 	
d.	0.228 	

ANS:	B
The partial pressure of nitrogen can be calculated by multiplying the barometric pressure by the percentage of nitrogen in the air, or 760 mm Hg ´ 0.78 = 592.8 mm Hg.

REF:	Page 15

76.	The partial pressure of oxygen when there is 25% oxygen in a gas mixture at an atmospheric pressure of 760 mm Hg is ____ mm Hg.
a.	190 	
b.	30.4 	
c.	1900 	
d.	159.6	

ANS:	A
Partial pressure of oxygen = % oxygen ´ barometric pressure, or 0.25 ´ 760 mm Hg = 190 mm Hg.

REF:	Page 15

77.	Which of the following does not follow Dalton’s law at sea level?
a.	Oxygen	
b.	Nitrogen	
c.	Water vapor	
d.	Trace gases	

ANS:	C
Water vapor pressure does not follow Dalton’s law because such pressure primarily depends upon temperature. Water vapor pressure must be subtracted from the total pressure of a given mixture if the gas mixture is saturated with water.

REF:	Page 15

78.	One mole of any gas will occupy 22.4 L and contain ________ molecules.
a.	6.02 ´ 1023	
b.	6.2 ´ 1023	
c.	0.602 ´ 1023	
d.	6.2 ´ 10-23	

ANS:	A
1 mole of oxygen (mw = 32 g) occupies a volume of 22.4 L and contains 6.02 ´ 1023 molecules when measured at 0° C (273° K) and 1 atm.

REF:	Page 15

79.	A practical application of Avogadro’s law is seen in the calculation of which of the following?
I. Specific gravity
II. Diffusion rate
III. Gas density
IV. Osmosis
a.	I and II 	
b.	I and III 	
c.	II and IV 	
d.	III and IV 	

ANS:	B
A practical application of Avogadro’s law is seen in the calculation of gas densities and specific gravity.

REF:	Page 15

80.	The molecular weight of a gas divided by 22.4 L is used to express:
a.	Density	
b.	Diffusion rate	
c.	Partial pressure	
d.	Specific gravity	

ANS:	A
The density of a gas per unit volume can be calculated with the following formula:
Density (gm/L) = mw of gas/22.4 L.

REF:	Page 15

81.	At what temperature would you expect to see the highest water-vapor pressure?
a.	0° C	
b.	40° C	
c.	100° C	
d.	Absolute zero	

ANS:	C
The higher the temperature, the more water vapor a gas can hold.

REF:	Page 15

82.	The movement of gas molecules from an area of high concentration to one of lower concentration describes the property of which of the following?
a.	Osmosis	
b.	Effusion	
c.	Diffusion	
d.	Suspension	

ANS:	C
Diffusion is movement of molecules from areas of high concentrations to low concentrations. Effusion refers to the seepage or loss of blood through torn blood vessels. Osmosis describes the movement of water across a semipermeable membrane from a less-concentrated to a more-concentrated area. Suspensions are mixtures of solutions with undissolved particles or molecules.

REF:	Page 15

83.	Which gas has the lowest specific gravity at 25° C and 760 mm Hg?
a.	Water vapor	
b.	Helium	
c.	CO2	
d.	O2	

ANS:	B
See Figure 1-13.

REF:	Page 15

84.	Which law states that when two gases are placed under the same temperature and pressure, the rates of diffusion of both gases are inversely proportional to the square root of their densities?
a.	Graham’s law	
b.	Henry’s law	
c.	Mole’s law (also known as the ideal gas law)	
d.	Fick’s law	

ANS:	A
Graham’s law states that when two gases are placed under the same temperature and pressure conditions, the rates of diffusion of the two gases are inversely proportional to the square root of their masses, or r1/r2 = where r1 and r2 represent the diffusion rates of the respective gases and M1 and M2 are the molar masses.

REF:	Page 16

85.	Which of the following formula(s) best represent(s) Graham’s law?

a.	I 	
b.	III 	
c.	II and IV 	
d.	III and IV 	

ANS:	C
Graham’s law states that when two gases are placed under the same temperature and pressure conditions, the rates of diffusion of the two gases are inversely proportional to the square root of their masses, or r1/r2 =, where r1 and r2 represent the diffusion rates of the respective gases, and M1 and M2 are the molar masses. If the mass of a gas is considered directly proportional to its density at a constant temperature and pressure, then r1/r2 = 2 where d1 and d2 are the densities of the gases in question.

REF:	Page 16

86.	In the formula for Henry’s law, the c represents which of the following?
a.	Mass	
b.	Density	
c.	Solubility	
d.	Partial pressure	

ANS:	A
c is the molar concentration (in mol/L) of the dissolved gas.

REF:	Page 16

87.	The law that describes the diffusion of a gas across a semipermeable membrane is _____ law.
a.	Fick’s 	
b.	Henry’s 	
c.	Graham’s 	
d.	Charles’ 	

ANS:	A
Fick’s law represents the flow of gases across semipermeable membranes. Henry’s law explains the relationship of a gas and a liquid in a combined space. Graham’s law involves the relationship of multiple gases placed under the same temperature and pressure, and Charles’ law states that the volume of gas varies directly with changes in temperature.
REF:	Page 16

88.	Fluid mechanics is a branch of physics that involves which of the following?
I. Hydrodynamics
II. Fluids in motion
III. Thermodynamics
IV. Electrical properties of gases
a.	II 	
b.	I and II 	
c.	I and IV 	
d.	III and IV 	

ANS:	B
Fluid mechanics deals with the behavior of fluids in motion and involves fluid dynamics. Hydrodynamics is the study of fluids in motion.

REF:	Page 17

89.	Which of the following terms does not describe a pattern of flow?
a.	Tubular	
b.	Laminar	
c.	Turbulent	
d.	Transitional	

ANS:	A
Tubular is the only word in the list that does not describe a pattern of flow.

REF:	Page 17

90.	When the movement of fluid molecules is streamlined, this flow is normally described as:
a.	Straight	
b.	Laminar	
c.	Turbulent	
d.	Aerodynamic	

ANS:	B
In laminar flow, the fluid flows in discrete cylindrical layers or streamlines. With turbulent flow, the movement of fluid becomes chaotic. Straight and aerodynamic are not terms that are used to describe the way fluid moves.

REF:	Page 17

91.	Fluid movement that is chaotic is known as:
a.	Random	
b.	Turbulent	
c.	Streamlined	
d.	Transitional	

ANS:	B
With turbulent flow, the movement of fluid molecules becomes chaotic and the orderly pattern of concentric layers seen with laminar flow is lost. Transitional flow is the mixture of laminar and turbulent flows. If the movement of fluid is said to be streamlined, it is laminar. Fluid mechanics does not describe the flow of fluids as being random.

REF:	Page 17

92.	When tubes have one or more branches, the flow becomes:
a.	Transitional	
b.	Restricted	
c.	Turbulent	
d.	Laminar	

ANS:	A
Transitional flow is a mixture of laminar and turbulent flows that typically occur where tubes divide. See Figure 1-15. Restricted flow occurs when narrowing or constrictions occur along the length of a tube. Laminar and turbulent flows can become restricted if an obstruction is encountered along the length of a tube.

REF:	Page 17

93.	The relationship between pressure, flow, and resistance for a liquid flowing through a tube represents:
a.	Reynolds’ number	
b.	Poiseuille’s law	
c.	Venturi principle	
d.	Bernoulli principle	

ANS:	B
When considering the flow of a liquid through a tube, you should take two factors into consideration: the driving pressure forcing the fluid and the resistance the liquid must overcome as it flows. Reynolds suggested that fluid flow becomes turbulent when velocity is increased or when there are changes in fluid density or viscosity and the radius of the tube. The Venturi and Bernoulli principles deal with the relationship between a liquid’s forward velocity and tubular lateral-wall pressure.

REF:	Page 17

94.	Applying the principles of Poiseuille’s law, which statement is true?
a.	The resistance offered by a tube is inversely proportional to its length.	
b.	As the radius of a tube decreases, the pressure gradient increases.	
c.	The more viscous the fluid, the easier it is to move the fluid through a tube.	
d.	The driving pressure of a gas is indirectly with the length of the tube.	

ANS:	B
Poiseuille’s law can be rewritten as: DP = Q ´ [(8nl)/(Pr4)]. According to this equation the following statements can be made. The more viscous a fluid, the greater the pressure gradient required to cause it to move through a given tube. The resistance offered by a tube is directly proportional to its length. The pressure required to achieve a given flow through a tube must increase in direct proportion to the length of the tube. The resistance to flow is inversely proportional to the fourth power of the radius. Small changes in the radius of a tube will cause profound increases in the resistance to flow through that tube.

REF:	Page 17

95.	When you discuss the mechanics of breathing, which expression of Poiseuille’s law do you use?
a.	P =  ´ R	
b.	 = P ÷ R	
c.	 = P ÷ R	
d.	 = 1/	

ANS:	C
Poiseuille’s law states that the pressure gradient required to cause a liquid to move through a tube is equal to the flow of the liquid through the tube multiplied by the resistance to flow. In a discussion of gases, the term flow of the liquid is replaced with flow of the gas. Therefore, the flow of the gas is equal to the pressure gradient divided by the resistance to flow.

REF:	Pages 17 and 18	

96.	Reynolds’ number is derived from which of the following components?
a.	Velocity of flow, radius of tube, density of gas, and velocity of gas	
b.	Velocity of flow, length of tube, density of gas, and velocity of gas	
c.	Velocity of gas, radius of tube, viscosity of flow, and density of gas	
d.	Flow asymmetry, shape of tube, density of gas, and length of tube	

ANS:	A
The formula for Reynolds’ number is NR = v ´ d ´ (2r/h), where v is the velocity of the flow; r is the radius of the tube, and d and h are the density and viscosity of the gas, respectively.

REF:	Page 18

97.	As a fluid flows through a tube of uniform diameter, pressure drops progressively over the length of the tube. This illustrates an application of which of the following?
a.	Coanda effect	
b.	Venturi principle	
c.	Bernoulli principle	
d.	Reynolds’ number	

ANS:	D
Bernoulli stated that “As the forward velocity of a gas, or liquid, moving through a tube increases, the lateral wall pressure of the tube will decrease.” Venturi postulated that pressure drops of fluids moving through constriction along a tube can be reversed if there is gradual dilation in the tube distal to the constriction. The Coanda effect is also based on the Bernoulli principle and demonstrates that water or gas flow can be deflected through a full 180° by careful placement of postconstriction extensions.

REF:	Page 18

98.	Following Bernoulli's principle, when a fluid approaches a constriction in a tube, there will be a(n) ____ in acceleration and a(n) ____ in lateral pressure.
a.	Decrease, decrease	
b.	Decrease, increase	
c.	Increase, decrease	
d.	Increase, increase	

ANS:	C
As fluid approaches a constriction in a tube, the flow of the liquid will accelerate (increase) as it enters the constriction, which in turn causes a decrease in lateral-wall pressure.

REF:	Page 18

99.	The pressure drop resulting from a constriction in a tube can be restored by which of the following?
a.	An increase in flow rate	
b.	Postconstriction increase in radius	
c.	Addition of an additional entrainment port	
d.	A further decrease in the radius of the tube	

ANS:	B
This question involves the Venturi principle, which states that the pressure drop caused by fluid flowing through a tubular constriction can be restored to preconstriction values by allowing for a gradual dilation in the tube.

REF:	Pages 18 and 19	

100.	Placement of postconstriction extensions in a tube can deflect a flow 180° along a new wall contour. This phenomenon illustrates the:
a.	Coanda effect	
b.	Venturi principle	
c.	Bernoulli principle	
d.	Bernoulli-Coanda inversion	

ANS:	A
Coanda was able to demonstrate that, with careful placement of the postconstriction extensions, he could deflect a stream of air through a full 180-degree turn by extending the wall contour.

REF:	Page 19

101.	Electricity can be represented by the flow of which of the following?
a.	Negative ions through a nonconductive path	
b.	Negative ions over a nonconductive circuit	
c.	Electrons through a piece of copper wire	
d.	Electrons in a bidirectional path	

ANS:	C
Electricity is produced by the flow of electrons through a conductive material such as copper. Electricity cannot flow through nonconductive material or simultaneously run bidirectionally along the same path.

REF:	Pages 19 and 20	

102.	An electric current is influenced by which of the following?
I. Voltage
II. Resistance
III. Electromotive forces
IV. The number of insulators
a.	I and II 	
b.	II and IV 	
c.	III and IV 	
d.	I, II, III, and IV	

ANS:	A
Electric currents are influenced by voltage (the electromotive force pushing electrons forward) and the resistance electrons must overcome along the conductive pathway. An insulator is the material surrounding the conductive material and is usually made of plastic.

REF:	Page 20

103.	The standard unit of measure of an electric current is which of the following?
a.	Milliampere	
b.	Coulomb	
c.	Ampere	
d.	Volt	

ANS:	C
The standard unit of measurement of electric current is the ampere (A), where 1A is equivalent to 6.25 ´ 1018 electrons passing a point in 1second. The term coulomb is used as a shorthand notation for 6.25 ´ 1018 electrons. The standard unit of measurement for voltage is the volt (V). A milliampere is equal to 0.001 A.

REF:	Page 20

104.	Which of the following correctly expresses Ohm’s law?
a.	R = I ´ V	
b.	V = R ´ I	
c.	I = V ´ R	
d.	V = I/R	

ANS:	B
The relationships among current, voltage, and resistance can be explained with Ohm’s law: V = I ´ R.

REF:	Page 20

105.	According to Ohm’s law, assuming that the voltage is held constant, what will happen to the resistance if the current is doubled?
a.	It will remain the same.	
b.	It will be doubled.	
c.	It will quadruple.	
d.	It will be halved.	

ANS:	D
Given the fact that when resistance is constant there is a direct relationship between voltage and current, when voltage is constant there is an indirect or inverse relationship between current and resistance. Therefore, if current is increased, resistance would have to decrease proportionately.

REF:	Page 20

106.	A major disadvantage of a series circuit is which of the following?
a.	It is limited to one load.	
b.	It can contain unlimited resistance.	
c.	Electrical current will stop if a break occurs anywhere along the path.	
d.	The circuit will remain up if a break occurs in one of the branches.	

ANS:	C
In a series circuit, there is only one path. If a break occurs anywhere in the path, the entire circuit will fail.

REF:	Page 20

107.	A series circuit contains a total resistance of 100 . If the circuit has three resistors and one of the resistors is 40 , what is the combined resistance of the last two resistors?
a.	60 	
b.	2.5 	
c.	140 	
d.	0.04 	

ANS:	A
According to Kirchhoff’s laws regarding series circuits, total resistance is equal to the sum of all resistors in the circuit. If the circuit has three resistors, total resistance = A+ B + C. Therefore, 100 = A + B + C. If one resistor is 40 , then 100 = 40 + B + C and the sum of B + C must equal 60 .

REF:	Pages 20 and 21	

108.	Which organ in the human body is most susceptible to electric shock?
a.	Skin	
b.	Heart	
c.	Brain	
d.	Lungs	

ANS:	B
Although all body tissues and organs are susceptible to electrical shock, the heart is the most vulnerable because it is governed by electricity.

REF:	Pages 21 and 22	

109.	Electrical hazards can be prevented by which of the following?
I. Properly grounding the circuit
II. Using ground fault circuit interrupters (GFCIs)
III. Using only Underwriters Laboratories (UL)–approved electrical equipment
IV. Using as many extension cords as necessary to keep the wires out of the way
a.	I and II 	
b.	III and IV 	
c.	II and III 	
d.	I, II, and III 	

ANS:	D
Grounding provides a path of least resistance that allows current to bypass the body in the event of a short circuit. GFCIs are circuit breakers that will trip when there is even a small difference between current flowing out through the device and current returning through the device. UL certifies devices that are plugged into current sources.

REF:	Page 22

110.	If 50% of the gas delivered to a patient is oxygen, its partial pressure at 1 atm is _____ mm Hg.
a.	265.0 	
b.	356.5 	
c.	380.0 	
d.	403.5 	

ANS:	C
The partial pressure of a gas in a mixture can be calculated by multiplying the total pressure of the mixture by the percentage of the mixture that the gas in question occupies. Therefore, 0.5 ´ 760 mm Hg = 380 mm Hg.

REF:	Page 14