Unit 3 - Chapter 18 - Introduction to Thermodynamics

Absolute pressure is the sum of __________ and __________ pressures. a) gauge, atmospheric b) standard, deviation c) minimum, maximum d) positive, negative e) above, below

A

Radiation from the furnace fire a) travels in straight lines b) is present in oil firing but not fuel gas firing c) radiates through the superheater tube walls d) radiates through the water in the water walls e) requires a transfer medium

A

The flow of heat from molecule to molecule within a substance or from molecules of one body to those of another body in direct contact with it is defined as a) conduction b) convection c) specific heat d) latent heat of fusion e) absolute pressure

A

The transfer of heat by __________ involves the movement of a fluid (a liquid or a gas). a) convection b) expansion c) conduction d) contraction e) radiation

A

Which of the following statements about heat is true? a) If there is a temperature difference between the heat source and a cooler object in contact with the source, heat will be transferred to the cooler object. b) Heat can be transferred from cold bodies to hot bodies without using an external supply of work. c) Specific heat is the same for every substance. d) Specific heat capacity is the same for every state of matter of the same substance. e) 1 J is less than 1 Nm of work.

A

__________ heat is heat that causes a change in the temperature of a substance without changing its state. a) Sensible b) Latent c) Super d) Intense e) Saturated

A

Sensible heat a) is the latent heat plus heat of evaporation b) causes a rise in temperature c) cannot be read on a thermometer d) is the latent heat of fusion e) does not exist in vapours

B

The first law of thermodynamics states that heat and work are a) not convertible b) mutually convertible c) sometimes convertible d) mildly convertible e) mutually fusible

B

The transfer of heat involving the movement of a fluid is defined as a) conduction b) convection c) radiation d) refrigeration e) super heating

B

When the temperature of an object is raised, its increase in area is proportional to its a) initial length and final temperature b) initial area and temperature rise c) volume and initial temperature d) initial length and temperature rise e) colour and shape

B

__________ heat is heat that causes a change of state of a substance without changing its temperature. a) Sensible b) Latent c) Super d) Intense e) Saturated

B

__________ steam is steam that is fully saturated with latent and sensible heat and has no water particles present. a) Wet saturated b) Dry saturated c) Super heated d) Sensibly heated e) Intensified

B

The metric absolute temperature at which all molecular motion is said to completely cease is a) -270 degrees C b) 0 degrees C c) 40 degrees C d) -460 degrees R e) 0 K

E

The second law of thermodynamics states that unaided, heat will only flow from __________. a) a cold substance to a hotter substance b) a warm substance to a hotter substance c) a hot substance to a hotter substance d) a cold substance to a colder substance e) a hot substance to a colder substance

E

__________ refers to the transmission of electromagnetic waves. a) Convection b) Expansion c) Conduction d) Contraction e) Radiation

E

Natural convection is a method of heat transfer where the movement of the fluids is due solely to the a) surface pressure b) difference in densities c) difference in heating time d) gravitational differences e) activity of the radiant rays

B

A bimetal thermometer consists of a) a filament that is compared to the object being measured b) two dissimilar metals welded together c) two dissimilar wires connected to a battery d) two copper wires connected together e) two silver wires and a ground strap

B

If a 286 m steel bar is increased from 2 degrees C to 390 degrees C, how much does the bar expand? (The coefficient of linear expansion of steel is 0.000012/degrees C). a) 9.88 m b) 1.33 m c) 2.93 m d) 7.23 m e) 15.74 m

B

In the second law of thermodynamics, if it is required to transfer heat from a cold substance to a hotter substance (as in refrigeration) then __________ must be supplied. a) internal energy b) external work c) higher temperature d) lower temperature e) moderate temperature

B

The __________ method of heat transfer involves the flow of heat from molecule to molecule within a substance or from the molecules of one body to those of another body which is directly in contact with the first body. a) convection b) expansion c) conduction d) contraction e) radiation

C

The amount of heat to raise the temperature of a unit mass of a substance 1 degree Celsius without changing the state of the substance is defined as a) latent heat b) saturation temperature c) specific heat d) absolute zero e) radiation

C

The coefficient of expansion of metals a) is a constant for all non-ferrous metals b) has the units "cm" per "m" c) is greater for aluminum than steel d) is the same for all metals e) requires a component of latent heat

C

The transfer of heat through emission of electromagnetic waves is defined as a) conduction b) convection c) radiation d) refrigeration e) molecular agitation

C

Which of the following statements is true? a) Water will only expand when its temperature is increased. b) Liquids will not contract when their temperatures lower. c) Coefficients of expansion for liquids change in value as the temperature changes. d) In general coefficients of expansion of solids are greater than those of liquids. e) Solids generally contract when their temperatures rise.

C

__________ heat is the amount of heat required to raise the temperature of a unit mass of a substance 1 degree Celsius without changing the state of the substance. a) Sensible b) Latent c) Specific d) Super e) Saturated

C

__________ zero is the temperature at which all molecular movement ceases. a) Positive b) Negative c) Absolute d) Minimum e) Maximum

C

In the first law of thermodynamics, heat supplied = increase in internal energy + __________. a) energy supplied b) energy absorbed c) work in d) work done e) work supplied

D

When the temperature of an object is raised, its increase in length is proportional to its a) initial length and initial temperature b) cross-sectional area and temperature c) volume and temperature rise d) initial length and temperature rise e) elasticity and its ductility

D

Which of the following statements about the laws of thermodynamics is false? a) Heat and work are mutually convertible b) Heat supplied = increase in internal energy + work done c) Heat will flow from a hot substance to a colder substance d) Refrigeration requires no external work supply e) none of the above

D

__________ pressure is the pressure exerted by the earth's atmosphere. a) Absolute b) Maximum c) Minimum d) Atmospheric e) Standard

D