1. Unit of thermal conductivity in M.K.S. units is
2. Unit of thermal conductivity in S.I. units is
3. Thermal conductivity of solid metals with rise in temperature normally
4. Thermal conductivity of non-metallic amor-phous solids with decrease in temperature
5. Heat transfer takes place as per -
6. When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by
7. When heat is transferred form hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by
8. Sensible heat is the heat required to
9. The insulation ability of an insulator with the presence of moisture would
10. When heat is Transferred by molecular collision, it is referred to as heat transfer by
11. Heat transfer in liquid and gases takes place by
12. Which of the following is the case of heat transfer by radiation
13. Heat is closely related with
14. Pick up the wrong case. Heat flowing from one side to other depends directly on
15. Metals are good conductors of heat because
16. Which of the following is a case of steady state heat transfer
17. Total heat is the heat required to
18. Cork is a good insulator because it has
19. Thermal conductivity of water in general with rise in temperature
20. Thermal conductivity of water at 20°C is of the order of
21. Temperature of steam at around 540°C can be measured by
22. Thermal conductivity of air at room temperature in kcal/m hr °C is of the order of
23. The time constant of a thermocouple is
24. Thermal conductivity of air with rise in temperature
25. Heat flows from one body to other when they have
26. The concept of overall coefficient of heat transfer is used in heat transfer problems of
27. In heat transfer, conductance equals conductivity (kcal/hr/sqm/°C/cm) divided by
28. The amount of heat flow through a body by conduction is
29. Which of the following has least value of conductivity
30. Which of the following is expected to have highest thermal conductivity
31. Thermal conductivity of glass-wool varies from sample to sample because of variation in
32. Thermal conductivity of a material may be defined as the
33. Which of the following has maximum value of thermal conductivity
34. Moisture would find its way into insulation by vapor pressure unless it is prevented by
35. Heat is transferred by all three modes of transfer, viz, conduction, convection and radiation in
36. According to Provost theory of heat exchange
37. The ratio of heat flow Q1/Q2 from two walls of same thickness having their thermal conductivities as ATj - 2K2 will be
38. Heat transfer by radiation mainly depends upon
39. Thermal diffusivity is ______.
40. Thermal diffusivity of a substance is .
41. Unit of thermal diffusivity is
42. Thermal conductivity of wood depends on
43. In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by
44. Film coefficient is defined as Inside diameter of tube
45. Heat conducted through unit area and unit thick face per unit time when temperature difference between opposite faces is unity,is called
46. The rate of energy emission from unit surface area through unit solid angle, along a normal to the surface, is known as
47. Emissivity of a white polished body in comparison to a black body is
48. A grey body is one whose absorptivity
49. Two balls of same material and finish have their diameters in the ratio of 2 : 1 and both are heated to same temperature and allowed to cool by radiation. Rate of cooling by big ball as compared to smaller one will be in the ratio of
50. A non-dimensional number generally associated with natural convection heat transfer is
51. LMTD in case of counter flow heat exchanger as compared-to parallel flow heat exchanger is
52. In heat exchangers, degree of approach is defined as the difference between tempera-tures of
53. In counter flow heat exchangers
54. A steam pipe is to be insulated by two insulating materials put over each other. For best results
55. Fourier's law of heat conduction is valid for
56. According of Kirchhoff's law,
57. All radiations in a black body are
58. According to Kirchoff's law, the ratio of emissive power to absorptivity for all bodies is equal to the emissive power of a
59. The concept of overall coefficient of heat transfer is used in case of heat transfer by
60. The unit of overall coefficient of heat transfer is
61. Joule sec is the unit of
62. The value of Portland number for air is about
63. The value of the wavelength for maximum emissive power is given by —
64. Log mean temperature difference in case of counter flow compared to parallel flow will be
65. The energy distribution of an ideal reflector at higher temperatures is largely in the range of
66. Total emissivity of polished silver compared to black body is
67. According to Stefan-Boltzmann law, ideal radiators emit radiant energy at a rate proportional to
68. Which of the following property of air does not increase with rise in temperature
69. The unit of Stefan Boltzmann constant is
70. In free con-vection heat transfer, Nusselt number is function of
71. Stefan Boltzmann law is applicable for heat transfer by
72. The thermal diffusivities for gases are generally
73. The thermal diffusivities for solids are generally
74. Thermal diffusivity of a substance is
75. The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as
76. According to Stefan's law, the total radiation from a black body per second per unit area is proportional to
77. According to Wien's law, the wavelength corresponding to maximum energy is proportion to
78. Depending on the radiating properties, a body will be white when
79. Depending on the radiating properties, a body will be black when
80. Depending on the radiating properties, a body will be opaque when
81. The total emissivity power is .defined as the total amount of radiation emitted by a black body per unit
82. The ratio of the energy absorbed by the body to total energy falling on it is called
83. 40% of incident radiant energy on the surface of a thermally transparent body is reflected back. If the transmissivity of the body be 0.15, then the emissivity of surface is
84. The amount of radiation mainly depends on
85. The emissive power of a body depends upon its
86. Two plates spaced 150 mm apart are maintained at 1000°C and 70°C. The heat transfer will take place mainly by
87. Absorptivity of a body will be equal to its emissivity
88. In regenerator type heat exchanger, heat transfer takes place by
89. A perfect black body is one which
90. Planck's law holds good for
91. If the temperature of a solid surface changes form 27°C to 627°C, then its emissive power changes in the ratio of
92. Depending on the radiating properties, body will be transparent when
93. A grey body is one whose absorptivity
2. Unit of thermal conductivity in S.I. units is
3. Thermal conductivity of solid metals with rise in temperature normally
4. Thermal conductivity of non-metallic amor-phous solids with decrease in temperature
5. Heat transfer takes place as per -
6. When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by
7. When heat is transferred form hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by
8. Sensible heat is the heat required to
9. The insulation ability of an insulator with the presence of moisture would
10. When heat is Transferred by molecular collision, it is referred to as heat transfer by
11. Heat transfer in liquid and gases takes place by
12. Which of the following is the case of heat transfer by radiation
13. Heat is closely related with
14. Pick up the wrong case. Heat flowing from one side to other depends directly on
15. Metals are good conductors of heat because
16. Which of the following is a case of steady state heat transfer
17. Total heat is the heat required to
18. Cork is a good insulator because it has
19. Thermal conductivity of water in general with rise in temperature
20. Thermal conductivity of water at 20°C is of the order of
21. Temperature of steam at around 540°C can be measured by
22. Thermal conductivity of air at room temperature in kcal/m hr °C is of the order of
23. The time constant of a thermocouple is
24. Thermal conductivity of air with rise in temperature
25. Heat flows from one body to other when they have
26. The concept of overall coefficient of heat transfer is used in heat transfer problems of
27. In heat transfer, conductance equals conductivity (kcal/hr/sqm/°C/cm) divided by
28. The amount of heat flow through a body by conduction is
29. Which of the following has least value of conductivity
30. Which of the following is expected to have highest thermal conductivity
31. Thermal conductivity of glass-wool varies from sample to sample because of variation in
32. Thermal conductivity of a material may be defined as the
33. Which of the following has maximum value of thermal conductivity
34. Moisture would find its way into insulation by vapor pressure unless it is prevented by
35. Heat is transferred by all three modes of transfer, viz, conduction, convection and radiation in
36. According to Provost theory of heat exchange
37. The ratio of heat flow Q1/Q2 from two walls of same thickness having their thermal conductivities as ATj - 2K2 will be
38. Heat transfer by radiation mainly depends upon
39. Thermal diffusivity is ______.
40. Thermal diffusivity of a substance is .
41. Unit of thermal diffusivity is
42. Thermal conductivity of wood depends on
43. In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by
44. Film coefficient is defined as Inside diameter of tube
45. Heat conducted through unit area and unit thick face per unit time when temperature difference between opposite faces is unity,is called
46. The rate of energy emission from unit surface area through unit solid angle, along a normal to the surface, is known as
47. Emissivity of a white polished body in comparison to a black body is
48. A grey body is one whose absorptivity
49. Two balls of same material and finish have their diameters in the ratio of 2 : 1 and both are heated to same temperature and allowed to cool by radiation. Rate of cooling by big ball as compared to smaller one will be in the ratio of
50. A non-dimensional number generally associated with natural convection heat transfer is
51. LMTD in case of counter flow heat exchanger as compared-to parallel flow heat exchanger is
52. In heat exchangers, degree of approach is defined as the difference between tempera-tures of
53. In counter flow heat exchangers
54. A steam pipe is to be insulated by two insulating materials put over each other. For best results
55. Fourier's law of heat conduction is valid for
56. According of Kirchhoff's law,
57. All radiations in a black body are
58. According to Kirchoff's law, the ratio of emissive power to absorptivity for all bodies is equal to the emissive power of a
59. The concept of overall coefficient of heat transfer is used in case of heat transfer by
60. The unit of overall coefficient of heat transfer is
61. Joule sec is the unit of
62. The value of Portland number for air is about
63. The value of the wavelength for maximum emissive power is given by —
64. Log mean temperature difference in case of counter flow compared to parallel flow will be
65. The energy distribution of an ideal reflector at higher temperatures is largely in the range of
66. Total emissivity of polished silver compared to black body is
67. According to Stefan-Boltzmann law, ideal radiators emit radiant energy at a rate proportional to
68. Which of the following property of air does not increase with rise in temperature
69. The unit of Stefan Boltzmann constant is
70. In free con-vection heat transfer, Nusselt number is function of
71. Stefan Boltzmann law is applicable for heat transfer by
72. The thermal diffusivities for gases are generally
73. The thermal diffusivities for solids are generally
74. Thermal diffusivity of a substance is
75. The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as
76. According to Stefan's law, the total radiation from a black body per second per unit area is proportional to
77. According to Wien's law, the wavelength corresponding to maximum energy is proportion to
78. Depending on the radiating properties, a body will be white when
79. Depending on the radiating properties, a body will be black when
80. Depending on the radiating properties, a body will be opaque when
81. The total emissivity power is .defined as the total amount of radiation emitted by a black body per unit
82. The ratio of the energy absorbed by the body to total energy falling on it is called
83. 40% of incident radiant energy on the surface of a thermally transparent body is reflected back. If the transmissivity of the body be 0.15, then the emissivity of surface is
84. The amount of radiation mainly depends on
85. The emissive power of a body depends upon its
86. Two plates spaced 150 mm apart are maintained at 1000°C and 70°C. The heat transfer will take place mainly by
87. Absorptivity of a body will be equal to its emissivity
88. In regenerator type heat exchanger, heat transfer takes place by
89. A perfect black body is one which
90. Planck's law holds good for
91. If the temperature of a solid surface changes form 27°C to 627°C, then its emissive power changes in the ratio of
92. Depending on the radiating properties, body will be transparent when
93. A grey body is one whose absorptivity
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