Engineering :: Heat Transfer
51.
A substance above critical temperature exists as
A.
Solid
B.
Liquid
C.
Dry vapour
D.
Wet vapour
E.
Gas
Answer: Option E
Explanation:
52.
There are two spheres of copper the ratio of their radii being 1 : 3 both at the same temperature. The ration of heat contents will be
Answer: Option D
Explanation:
53.
When analogy is drawn between heat flow and electricity flow in circuits, the heat flow of thermal circuits is equated in the electrical circuit against
A.
Voltage
B.
Current
C.
Resistance
D.
Charge (coulombs)
Answer: Option B
Explanation:
54.
Thermal diffusivity is least for
Answer: Option A
Explanation:
55.
The lower temperature limit for mercury thermometer is
Answer: Option C
Explanation:
56.
For temperature below -40?C which one of the following substance can be used as thermometric substance
A.
Alcohol
B.
Pentane
C.
Ether
D.
Any of the above
E.
None of the above
Answer: Option D
Explanation:
57.
Heat is transferred from an insulated pipe to the surrounding still air mainly by
A.
Conduction
B.
Free convection
C.
Forced convection
D.
Radiation
E.
All above together
Answer: Option B
Explanation:
58.
Non-dimensional number generally involved in case of heat transfer from horizontal cylinder by natural convection is
A.
Reynolds number
B.
Nusselt number
C.
Prandtl number
D.
Grashof's numbr
E.
(B), (C) and (D) above
Answer: Option E
Explanation:
59.
Transformer oil having kinematic viscosity of 3.66 x 10-6 m2/s flows through a tube 8 mm diameter at velocity of 0.6 m/s. The value of Reynolds number of flow would be
Answer: Option B
Explanation:
60.
The nature of flow of a fluid inside a tube i.e., whether it is turbulent or laminar, is ascertained by
A.
Flow velocity
B.
Tube size
C.
Surface conditions
D.
Viscosity of fluid
E.
Reynolds number
Answer: Option E
Explanation:
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