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3A1 > 351-400 > Flashcards

351-400 Flashcards

1
Q
  1. With the exception of water, all liquids expand ____________ to temperature change when heated.

a. in direct proportion
b. faster
c. inversely proportional
d. slower
e. exponentially

A

a. in direct proportion

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2
Q
  1. The change in length per unit length per degree rise in temperature is known as the:

a. Specific heat
b. Coefficient of linear expansion
c. Coefficient of conductivity
d. Latent heat of fusion
e. Latent heat of evaporation

A

b. Coefficient of linear expansion

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3
Q
  1. One factor that determines the amount of thermal expansion of an object is the nature of the material itself. Through experimentation, each material is assigned a coefficient value, which is then applied to expansion calculations involving that material.

a. True
b. False

A

a. True

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4
Q
  1. The amount of increase in area of each surface will depend on the:

a. Rate of thermal conductivity.
b. Time allowed for heating.
c. Coefficient of surface expansion.
d. Change of thickness of the material.
e. Specific heat.

A

c. Coefficient of surface expansion.

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5
Q
  1. What is the coefficient expansion for glass?

a. 10.4 X 10-6
b. 19.5 x 10-6
c. 9.4 x 10-4
d. 9.0 x 10-6
e. None of the above

A

d. 9.0 x 10-6

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5
Q
  1. A copper rod of the same dimensions as a steel rod will:

a. Expand more for a given temperature change.
b. Expand less for a given temperature change.
c. Heat up slower for a given amount of heat.
d. Have the same mass.
e. Expand the same at all temperatures.

A

a. Expand more for a given temperature change.

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6
Q
  1. Expansion will result in an increase in a body’s surface as well as its ________________.

a. temperature
b. coefficient
c. volume
d. pressure
e. location

A

c. volume

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7
Q
  1. The coefficient of expansion for solids is______________.

a. constant for all solids
b. or has the same result for all metals
c. or has no bearing on the volumetric expansion
d. that we have different values for different substances.
e. that it can be determined by the formula Cp/Cv.

A

d. that we have different values for different substances.

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8
Q
  1. Heat will flow from a hot substance to a colder substance unaided, but it is impossible for heat to flow from a cold substance to a hotter one without the aid of mechanical work is:

a. The First Law of Thermodynamics
b. Charles’ Law
c. The mechanical equivalent of heat
d. The Second Law of Thermodynamics
e. The General Gas Law

A

d. The Second Law of Thermodynamics

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9
Q
  1. The Second Law of Thermodynamics deals with:

a. Speed of heat flow
b. Type of heat flow
c. Work and heat conversion
d. Quantity of heat flow
e. Direction of heat flow

A

e. Direction of heat flow

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10
Q
  1. Transfer of heat by convection depends upon:

a. The molecular structure of the fluid.
b. A dense fluid being displaced by a less dense fluid.
c. The color and the texture of the surface of the fluid.
d. The viscosity of the fluid.
e. A less dense fluid being displaced by a denser fluid.

A

e. A less dense fluid being displaced by a denser fluid.

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10
Q
  1. Heat will always flow between two bodies if they are ___________________.

a. at different temperatures
b. different colors
c. close to each other
d. in a solid state or phase only
e. of the same material in construction

A

a. at different temperatures

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10
Q
  1. The three methods by which transfer of heat energy takes place is:
1.     Convection
2.     Sensible
3.     Conduction
4.     Latent
5.     Enthalpy
6.     Radiation

a. 1, 4, 6
b. 2, 3, 5
c. 1, 3, 6
d. 3, 4, 6
e. 2, 4, 5

A

c. 1, 3, 6

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11
Q
  1. Conduction of heat takes place:

a. From ion to ion within the substance.
b. By a difference in densities of the substance.
c. In straight lines much like the sun’s rays.
d. By convection currents.
e. None of the above

A

e. None of the above

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12
Q
  1. The transfer of heat by convection involves the:

a. Reduction of mass
b. Movement of a fluid
c. Transfer of elements
d. Radiation of light
e. Contact between molecules

A

b. Movement of a fluid

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13
Q
  1. Radiation refers to:

a. Mechanical energy transmission.
b. The transmission of energy waves.
c. Transfer of heat from molecule to molecule.
d. Transfer of heat by different densities.
e. Transfer of heat by fluid flow.

A

b. The transmission of energy waves.

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14
Q
  1. Radiant energy waves are:

a. Able to pass through a vacuum.
b. Those that travel in straight lines.
c. Absorbed, reflected or transmitted by other bodies.
d. Absorbed and converted into heat.
e. All of the above

A

e. All of the above

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15
Q
  1. ___________ has the lowest thermal conductivity.

a. Aluminum
b. Brass
c. Copper
d. Air
e. Steel

A

d. Air

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16
Q
  1. The thermal conductivity is a property of a material and has a different value for each different material.

a. True
b. False

A

a. True

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17
Q
  1. The rate at which the heat flow takes place by conduction depend upon the temperature difference and the ____________________________.

a. thickness through which the flow takes place
b. type of material through which the flow takes place
c. area of the object the heat flows through
d. temperature difference through the material
e. All of the above

A

e. All of the above

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18
Q
  1. The ratio of the coefficient of volumetric expansion of a material to the coefficient of linear expansion of the same material is:

a. The square of the coefficient of linear expansion.
b. The cube of the coefficient of linear expansion.
c. 2 to 1
d. 3 to 1
e. 9 to 1

A

d. 3 to 1

19
Q
  1. If a mild steel cube of side 40 mm is heated from 25°C to 50 °C, the increase in volume will be?

a. 5.76 cu mm
b. 19.2 cu mm
c. 57.6 cu mm
d. 192 cu mm
e. 64 000 cu mm

A

c. 57.6 cu mm

20
Q
  1. A 110 m long mild steel pipe in a refinery conveys oil at a maximum temperature of 140°C. In the winter the plant is shut down, and the temperature of the pipeline drops to -25°C. Calculate the amount of shrinkage of the pipe.

a. 0.151 8 cm
b. 0.217 8 cm
c. 15.18 cm
d. 21.78 cm
e. 65.34 cm

A

d. 21.78 cm

20
Q
  1. The coefficient of volumetric expansion for solids is:

a. The cube of the coefficient of linear expansion.
b. Three times the coefficient of linear expansion.
c. Two times the coefficient of linear expansion.
d. The inverse of the coefficient of linear expansion.
e. The square root of the coefficient of linear expansion.

A

b. Three times the coefficient of linear expansion.

21
Q
  1. The coefficient of linear expansion is defined as:

a. A change in length per unit length for one degree of temperature change.
b. A rate of change per unit length per degree of temperature change.
c. A change in volume per unit volume for one degree of temperature change.
d. The difference in potential between two dissimilar metals.
e. The inverse of the specific volume of a substance.

A

a. A change in length per unit length for one degree of temperature change.

22
Q
  1. If the temperature of a mild steel bar 10 m long is increased from 15 to 75°C, the change in length will be?

a. 0.72 mm
b. 7.2 mm
c. 7.2 cm
d. 72 cm
e. 0.072 m

A

c. 7.2 cm

23
Q
  1. Heat transfer due to movement of a fluid is called ____________.

a. sublimation
b. convection
c. radiation
d. sensible heat
e. conduction

A

b. convection

24
Q
  1. Heat transfer directly from a flame in a furnace to the furnace waterwalls is an example of _______________.

a. convection
b. radiation
c. conduction
d. sublimation
e. condensation

A

b. radiation

25
Q
  1. If a bar is heated at one end, heat will travel from molecule to molecule until the other end becomes hot. This is known as _________________.

a. convection
b. radiation
c. conduction
d. specific heat
e. sublimation

A

c. conduction

26
Q
  1. Heat transfer by electromagnetic waves is called ____________.

a. radiation
b. conduction
c. convection
d. emission
e. electromagnetic transmission

A

a. radiation

27
Q
  1. Of four plates of identical physical dimensions, the one made of which material will conduct the most heat?

a. Aluminum
b. Brass
c. Copper
d. Glass
e. Steel

A

c. Copper

28
Q
  1. From the following list, IDENTIFY the three methods of heat energy transfer:
1.     Radiation
2.     Conduction
3.     Induction
4.     Convection
5.     Sublimation

a. 1, 3 and 4
b. 1, 2 and 4
c. 1, 2 and 5
d. 2, 3 and 4
e. 3, 4 and 5

A

b. 1, 2 and 4

29
Q
  1. Heat supplied or taken away from a substance that causes a change of state without a change in temperature is called _______________.

a. latent heat
b. sensible heat
c. convective heat
d. accumulated heat
e. evaporative heat

A

a. latent heat

30
Q
  1. Addition of sensible heat to a substance:

a. Results in a change of state from solid to liquid.
b. Cannot be read on a thermometer.
c. Causes a rise in temperature.
d. Is the sum of the latent heat plus heat of evaporation.
e. Results in a change of phase from liquid to vapor.

A

c. Causes a rise in temperature.

31
Q
  1. The heat necessary to change a unit mass of liquid to the vapor state without any change in the temperature and pressure is the _________________.

a. latent heat of evaporation
b. boiling temperature
c. sensible heat
d. enthalpy of fusion
e. fusion energy

A

a. latent heat of evaporation

32
Q
  1. Steam at its boiling point with no water particles present is called _____________.

a. dry saturated steam
b. supersaturated
c. superheated
d. vaporized
e. wet saturated steam

A

a. dry saturated steam

33
Q
  1. The temperature at which water boils is dependent upon the ________________.

a. heat content
b. acting pressure
c. total boiler heating surface
d. absolute volume
e. boiling index

A

b. acting pressure

34
Q
  1. Superheated steam is steam at a certain pressure, which temperature is above the ______________.

a. combustion gas temperature
b. radiant steam temperature
c. fusion temperature
d. saturation temperature
e. critical temperature

A

d. saturation temperature

35
Q
  1. The value in the steam tables corresponding to a temperature of 374.12°C and pressure of 22, 090 kPa is called the _________of steam.

a. critical point
b. boiling point
c. superheat pressure and temperature
d. steam - water saturation point
e. point of absolute temperature and pressure

A

a. critical point

36
Q
  1. The amount of heat required to convert 10 kg of water at 60°C into saturated steam at 200 kPa is?

a. 2455.57 kJ
b. 2511.3 kJ
c. 2706.7 kJ
d. 24 554.7 kJ
e. 27 067 kJ

A

d. 24 554.7 kJ

36
Q
  1. Determine the total latent heat of 2.3 kg of steam at a pressure of 350 kPa absolute.

a. 6284.5 kJ
b. 4940.6 kJ
c. 2148.1 kJ
d. 1649.9 kJ
e. 1343.9 kJ

A

b. 4940.6 kJ

37
Q
  1. 1 kg of saturated steam at 200 kPa absolute has a dryness fraction of 95%. Calculate the total heat content.

a. 2706.7 kJ
b. 2611.3 kJ
c. 2596.5 kJ
d. 2589.91 kJ
e. 2091.8 kJ

A

c. 2596.5 kJ

38
Q
  1. Five kilograms of water at 100°C is changed to saturated steam having a final temperature of 120°C. Calculate the total amount of heat required in changing the water to steam.

a. 2287.26 kJ
b. 2706.3 kJ
c. 11 436 kJ
d. 13 531.5 kJ
e. 17 138 kJ

A

c. 11 436 kJ

39
Q
  1. The quantity of saturated water contained in a unit quantity of steam is indicated by the _____________.

a. partial pressure
b. dryness fraction
c. saturation index
d. steam temperature
e. moisture index

A

b. dryness fraction

40
Q
  1. The ratio of the heat energy required to make steam to the heat energy supplied by the combustion of fuel in a boiler is called ________________.

a. boiler efficiency
b. factor of evaporation
c. heat rate
d. combustion efficiency
e. equivalent evaporation

A

d. combustion efficiency

41
Q
  1. A boiler generates 8 kg of dry saturated steam per kg of fuel oil burned. Fuel oil heating value is 33 000 kJ/kg. Feedwater is supplied at 70°C, and the boiler pressure is 1400 kPa. Calculate the boiler efficiency.

a. 57.3%
b. 60.5%
c. 74.7%
d. 85.0%
e. 92.3%

A

b. 60.5%

42
Q
  1. What is the specific volume of dry saturated steam at 250 kPa?

a. 560 cm3/gm
b. 560 m3/kg
c. 718 cm3/gm
d. 71.8 m3/kg

A

c. 718 cm3/gm

43
Q
  1. The dryness fraction, also called steam quality, is the percentage:

a. By weight of steam in the mixture
b. By volume of water to steam in the mixture
c. By volume of steam in the mixture
d. Of water by weight in the steam

A

a. By weight of steam in the mixture

44
Q
  1. The total heat for wet steam can be determined by:

a. Multiplying hg by the dryness fraction.
b. Using the entropy - enthalpy diagram for steam.
c. Multiplying the hf value from the Steam Table by the dryness fraction.
d. Subtracting the volume of water from the volume of steam and multiplying the result by the dryness fraction.

A

b. Using the entropy - enthalpy diagram for steam.

45
Q
  1. Steam that is superheated:

a. Has a greater volume than saturated steam.
b. Has more sensible heat than saturated steam at the same pressure.
c. Contains more energy and has a higher temperature than saturated steam.
d. All of the above

A

d. All of the above

3A1 (12 decks)

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