PIPE Elements (Chapter 13: Heat Transfer)

1. One of the reasons for insulating the
   pipes is:
   A. They may not break under pressure
   B. There is minimum corrosion
   C. Capacity to withstand pressure is
   increased
   D. Heat loss from the surface is minimized

D. Heat loss from the surface is minimized

2. The rate of radiant energy, that is emitted by a
   surface at any temperature and in small
   wavelengths is found from the known rate of
   energy that under the same conditions will be
   emitted from a black surface, by multiplying with
   the absorptivity.
   The above enunciation is called:
   A. Lambert's law
   B. Kirchhoff's law
   C. Planck's law
   D. Stefan Boltzmann's law

B. Kirchhoff's law

3. Which of the following is generally used
   to measure the temperature inside the
   furnace?
   A. Mercury thermometer
   B. Alcohol thermometer
   C. Ash thermometer
   D. Optical pyrometer

D. Optical pyrometer

4. All heat transfer processes:
   A. Involve transfer of energy
   B. Involve temperature difference between
   the bodies
   C. Obey first law of thermodynamics
   D. Obey second law of thermodynamics

B. Involve temperature difference between the bodies

5. What is thermal diffusivity?
   A. A mathematical formula
   B. A physical property of the material
   C. A configuration for heat conduction
   D. A dimensionless parameter

B. A physical property of the material

6. Which of the following is a unit of
   thermal diffusivity?
   A. $m^2/hr$
   B. $kcal/m^2hr$
   C. $kcal/m^2hr^\circ C$
   D. $m^2/hr^\circ C$

A. $m^2/hr$

7. Non-isotropic conductivity is shown
   by which of the following?
   A. Brass
   B. Copper
   C. Wood
   D. Steel

C. Wood

8. For glass wool thermal conductivity
   changes from sample to sample due to
   changes in:
   A. Structure
   B. Density
   C. Composition
   D. All of the above

D. All of the above

9. Which of the following is the S.I. unit
   of thermal conductivity?
   A. $W/m-hr-^\circ K$
   B. $W/m^\circ K$
   C. $KJ/m-hr-^\circ C$
   D. $W/m-hr-^\circ C$

B. $W/m^\circ K$

10. What is the value of the Prandt’l
    number for air?
    A. 10
    B. 6.7
    C. 67
    D. 0.7

D. 0.7

11. According to Prevost theory of heat
    exchange,
    A. It is impossible to transfer heat from low
    temperature source to high temperature
    source
    B. Heat transfer by radiation needs no medium
    C. All bodies above absolute zero emit radiation
    D. Heat transfer in most of the cases occurs by
    combination of conduction, convection and
    radiation

C. All bodies above absolute zero emit radiation

12. Thermal conductivity of wood
    depends on which of the following?
    A. Moisture
    B. Temperature
    C. Density
    D. All of the above

D. All of the above

13. A fur coat on an animal will help
    the animal to remain:
    A. Warm in winter
    B. Cool in winter
    C. Warm in summer
    D. Cool in summer

A. Warm in winter

14. The nature of flow of a fluid inside
    a tube, whether it is turbulent or
    laminar, can be ascertained by:
    A. Flow velocity
    B. Surface conditions
    C. Viscosity of fluid
    D. Reynolds number

D. Reynolds number

15. By which of the following modes of
    heat transfer is the Stefan-Boltzmann
    law applicable?
    A. Conduction
    B. Radiation
    C. Conduction and radiation combined
    D. Convection and radiation combined

B. Radiation

16. At all wave lengths and
    temperatures the monochromatic
    emissivity of a white body is equal to:
    A. Zero
    B. 0.5
    C. Unity
    D. 0.1 to 0.5

A. Zero

17. The radiation from flames is having
    A. Continuous radiation from burning soot
    particles of microscopic and submicroscopic
    dimensions
    B. Radiation from suspended larger particles of
    coal, coke, or ash contributing to flame
    lumininossity
    C. Infared radiation from water vapor and
    carbon dioxide
    D. All of the above

D. All of the above

18. The statement that the emissivity and
    absorptivity of a surface is surrounded by
    its own temperature are the same for
    both monochromatic and total radiation
    is called:
    A. Lambert’s law
    B. Kirchhoff’s law
    C. D’Alambart’s
    D. Law of emissivity

B. Kirchhoff’s law

19. A reservoir that supplies energy
    in the form of heat is called:
    A. Source
    B. Sink
    C. Cold reservoir
    D. Heat reservoir

A. Source

20. In regenerator type heat exchanger,
    heat transfer occurs by:
    A. Direct mixing of hot and cold fluids
    B. A complete separation between hot and
    cold fluids
    C. Flow of hot and cold fluids alternately
    over a surface
    D. Generation of heat again and again

C. Flow of hot and cold fluids alternately over a surface

21. Least value of Prandt’l number can
    be expected in case of
    .
    A. Liquid metals
    B. Sugar solution
    C. Salt solution
    D. Water

A. Liquid metals

22. “The boiling point of a solution is a
    linear function of water at the same
    pressure.”
    The above statement is called
    ___.
    A. Dubring’s rule
    B. Petit and Dulong’s law
    C. Fick’s rule
    D. Reynolds law

A. Dubring’s rule

23. Floating heads are provided in heat
    exchangers to
    A. Increase the pressure drop
    B. Decrease the pressure drop
    C. Facilitate maintenance
    D. Avoid deformation of tubes because
    of thermal expansion

D. Avoid deformation of tubes because of thermal expansion

24. What do you call the first stage of
    crystal formation?
    A. Nucleation
    B. Foaming
    C. Separation
    D. Vortexing

A. Nucleation

25. In heat exchanger design, one transfer unit
    implies:
    A. One fluid which is exchanging with another fluid
    of the same chemical composition
    B. The section of heat exchanger which will cause
    temperature drop of one degree centigrade
    C. The section of heat exchanger where heat
    transfer surface area has been one square meter
    D. Condition when the change in temperature of
    one steam is numerically equal to the average
    driving force

D. Condition when the change in temperature of one steam is numerically equal to the average driving force

26. Dritus Boelter equation can be
    applied in case of fluids flowing in:
    A. Transition region
    B. Turbulent region
    C. Laminar region
    D. Any of the above

B. Turbulent region

27. In sugar mills can just is
    evaporation in:
    A. Zigzag tube evaporators
    B. Long vertical tube evaporators
    C. Short vertical tube evaporators
    D. Horizontal tube evaporators

B. Long vertical tube evaporators

28. A 1-2 heat exchanger refers to which of the
    following?
    A. Single pass on shell side and double pass on
    tube side
    B. Single pass on tube side and double pass on
    shell side
    C. Single liquid cools two liquids at different
    temperature
    D. Two tubes of cold fluid pass through one
    tube of hot fluid

A. Single pass on shell side and double pass on tube side

29. A correction of LMTD is
    essential in case of:
    A. Parallel flow heat exchanger
    B. Counter current heat exchanger
    C. Cross flow heat exchanger
    D. None of the above

C. Cross flow heat exchanger

30. Which of the following is used as
    entrainer in acetic acid – water
    separation?
    A. Methyl alcohol
    B. Phosphorous
    C. Butyl acetate
    D. Hexane

C. Butyl acetate

31. A type of radiation consisting of
    singly charged particles that generate
    to intermediate distances.
    A. Nuclear radiation
    B. Alpha radiation
    C. Beta radiation
    D. Gamma radiation

C. Beta radiation

32. An electrically charged atom or
    radical which carries electricity
    through an electrolyte is called:
    A. Ion
    B. Isotope
    C. Molecule
    D. Hole

A. Ion

33. The energy of a body that can be
    transmitted in the form of heat.
    A. Heat energy
    B. Thermal energy
    C. Entropy
    D. Internal energy

B. Thermal energy

42. Thermal conduction is described by:
    A. Newton’s law
    B. The logarithmic mean temperature difference
    C. The Stefan-Boltzmann law
    D. Fourier’s law

D. Fourier’s law

43. Convection is described by which of the following laws?
    A. Newton’s law
    B. The logarithmic mean temperature difference
    C. The Stefan-Boltzmann law
    D. Fourier’s law

A. Newton’s law

44. Radiation heat transfer is described by
    A. Newton’s law
    B. The logarithmic mean temperature difference
    C. Fourier’s law
    D. Kirchhoff's law

D. Kirchhoff's law

53. The term “exposure” in radiological effects is used as a measure of a gamma ray or an X-ray field in the surface of an exposed object.
    Since this radiation produces ionization of the air surrounding the object, the exposure is obtained as
    A. Number of ions produced per mass of air x coulombs per kg
    B. Mass of air x surface area of an exposed object
    C. Mass of air over surface area of an exposed object
    D. Number of ions produced per mass of air + coulombs per kg

A. Number of ions produced per mass of air x coulombs per kg

62. The transmission of heat from one place to another by fluid circulation between the spots of different temperature is called _.
    A. Convection
    B. Conservation
    C. Radiation
    D. Conduction

A. Convection

63. Which of the following requires the greatest amount of heat per kilogram for a given increase in temperature?
    A. Ice
    B. Water
    C. Steam
    D. Copper

B. Water

71. In the process of freeze drying, ice goes directly into water vapor.
    What is the temperature at which this process can take place?
    A. Below the triple point of water
    B. At the triple point of water
    C. Above the triple point of water
    D. Any of the above, depending on the pressure

A. Below the triple point of water

81. Which of the following is the Stefan-Boltzmann constant?
    A. $5.77\times 10^{-7} W/m^2K^4$
    B. $7.67\times 10^{-4} W/m^2K^4$
    C. $4.78\times 10^{-10} W/m^2K^4$
    D. $5.67\times 10^{-8} W/m^2K^4$

D. $5.67\times 10^{-8} W/m^2K^4$

82. What is the usual value of transmissivity for opaque materials?
    A. 0
    B. Indeterminate
    C. 1
    D. Infinity

A. 0

90. It is the term used to describe the energy of a body that can be transmitted in the form of heat.
    A. Enthalpy
    B. Thermal energy
    C. Entropy
    D. Internal energy

B. Thermal energy

91. Which of the following is the equivalent heat transferred of a gas undergoing isometric process?
    A. Change in enthalpy
    B. Change in entropy
    C. Change in internal energy
    D. Work nonflow

C. Change in internal energy

99. What refers to a form of energy associated with the kinetic random motion of large numbers of molecules?
    A. Heat
    B. Heat of fusion
    C. Entropy
    D. Internal energy

A. Heat

100. How much id the part of light that is absorbed by the body that transmits and reflects 80% and 10% respectively?
     A. 10%
     B. 30%
     C. 20%
     D. 5%

A. 10%

107. Two metals were kept together at room temperature and it was found out that one is colder than the other.
     Which of the following is the best reason why one metal is colder than the other?
     A. The heat transfer coefficient of one metal is of higher
     B. One metal is of lower temperature as compared to the other
     C. One metal is of higher temperature as compared to the other
     D. The thermal conductivity of one metal is high as compared to the other

D. The thermal conductivity of one metal is high as compared to the other

114. Which of the following is the science of low temperatures?
     A. Cryogenics
     B. Thermo-kinetics
     C. Thermodynamics
     D. Ergonomics

A. Cryogenics

115. Which of the following thermal state of the body considered as reference to communicate heat to the other bodies?
     A. Temperature
     B. Pressure
     C. Internal energy
     D. Entropy

A. Temperature

116. The true mean temperature difference is also known as:
     A. The average mean temperature difference
     B. The logarithmic mean temperature difference
     C. The trigonometric mean temperature difference
     D. The exponential temperature difference

B. The logarithmic mean temperature difference

124. Which of the following is the reason why metals are good conductors of heat?
     A. Metals contain free electrons
     B. Metals have atoms the frequently collide another
     C. Metals have reflecting surfaces
     D. Atoms in metals are very far to each other

A. Metals contain free electrons

125. The rate at which heat flows through a slab of some material does not depend on which of the following?
     A. The thickness of the slab
     B. The area of the slab
     C. The temperature difference between two faces
     D. The specific heat of the material

D. The specific heat of the material

137. Which of the following is not a
     heat exchanger?
     A. Condenser
     B. Boilers
     C. Evaporators
     D. Water hammer

D. Water hammer

138. Which of the following heat
     exchangers where fluid flow in the same
     direction and both are of changing
     temperatures?
     A. Parallel flow
     B. Cross flow
     C. Counter flow
     D. Mixed flow

A. Parallel flow

139. What happens to the thermal
     conductivity of diatomic gases if the
     temperature is increase?
     A. The thermal conductivity will also increase
     B. The thermal conductivity decreases
     C. The thermal conductivity remains constant
     D. The thermal conductivity partially
     increases then decreases

A. The thermal conductivity will also increase

140. What device is used to measure
     the amount of infrared radiation in
     each portion of a person’s skin that is
     emitted?
     A. Thermograph
     B. Thermometer
     C. Pyrometer
     D. Potentiometer

A. Thermograph

141. The heat transfer by convection
     occurs in which of the following?
     A. Only in gases
     B. Only in liquids
     C. Only in gases and liquids
     D. Only in gases and solids

C. Only in gases and liquids

142. In convection heat transfer, what mechanism heat transfer where the fluid moves due to the decrease in its density caused by increase in temperature?
     A. Forced convection
     B. Natural convection
     C. Density convection
     D. Radial convection

B. Natural convectio