Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning

16.
Which of the following refrigerant has the highest freezing point.
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
Answer: Option
Explanation:
No answer description is available. Let's discuss.

17.
Air conditioning means
cooling
heating
dehumidifying
all of these
Answer: Option
Explanation:
No answer description is available. Let's discuss.

18.
The emissivity for a black body is
0
0.5
0.75
1
Answer: Option
Explanation:
No answer description is available. Let's discuss.

19.
Which of the following would lead to a reduction in thermal resistance?
In conduction, reduction in the thickness of the material and an increase in thermal conductivity.
In convection, stirring of the fluid and cleaning the heating surface.
In radiation, increasing the temperature and reducing the emissivity.
all of the above
Answer: Option
Explanation:
No answer description is available. Let's discuss.

20.
The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number)n, where n is equal to
-1/3
-2/3
1
-1
Answer: Option
Explanation:
No answer description is available. Let's discuss.