Engineering :: Heat Transfer
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81. |
The average heat transfer coefficient for dropwise condensation is |
A. |
more than that for filmwise condensation |
B. |
less than that for filmwise condensation |
C. |
nearly same as that for filmwise condensation |
D. |
always less than 40 Btu/(hr. ft2 ?F) |
Answer: Option A
Explanation:
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82. |
The heat flux in the free convection regime of pool boiling varies as the |
Answer: Option C
Explanation:
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83. |
The peak heat flux in a boiling curve is called |
A. |
the burnout point |
B. |
the Leidenfrost point |
C. |
the boiling point |
D. |
the Nusselt point |
Answer: Option A
Explanation:
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84. |
The surface tension of water |
A. |
is independent of temperature |
B. |
decreases with increasing temperature |
C. |
increases with increasing temperature |
D. |
decreases linearly with increasing temperature |
Answer: Option B
Explanation:
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85. |
At atmospheric pressure the critical temperature drop for water is usually between |
A. |
70 and 90?F |
B. |
70 and 90?C |
C. |
40 and 50?F |
D. |
180 and 212?F |
Answer: Option A
Explanation:
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86. |
The transfer of heat energy from a heated body to a colder body by the emission of heat waves is called |
A. |
conduction |
B. |
natural convection |
C. |
forced convection |
D. |
radiation |
Answer: Option D
Explanation:
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87. |
Heat waves |
A. |
travel only in straight lines |
B. |
travel only in circular lines |
C. |
involve some kind of matter to carry the heat energy |
D. |
travel in haphazard manner |
Answer: Option A
Explanation:
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88. |
Heat transfer by radiation is described by |
A. |
Newtons law of cooling |
B. |
Ficks law |
C. |
Fouriers law |
D. |
Stefan-Baltzmann law |
Answer: Option D
Explanation:
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89. |
According to Stefan-Baltzmann law the radiant heat transfer is proportional to |
A. |
the absolute temperature |
B. |
the second power of the absolute temperature |
C. |
third power of the absolute temperature |
D. |
the fourth power of the absolute temperature |
Answer: Option D
Explanation:
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90. |
The Stefan-Baltzmann constant (?) is independent of |
A. |
surface |
B. |
medium |
C. |
temperature difference and thickness only |
D. |
all of the above |
Answer: Option D
Explanation:
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