2 bar
8 bar
15 bar
30 bar
✅ The correct answer is option B.
Heat Transfer
Which of the following refrigerant has the highest freezing point.
Ammonia
Carbon dioxide
Sulphur dioxide
R-12
✅ The correct answer is option B.
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
✅ The correct answer is option D.
During sensible cooling,
relative humidity remains constant
wet bulb temperature increases
specific humidity increases
partial pressure of va
✅ The correct answer is option D.
The cooling system used for supersonic aircrafts and rockets is
simple air cooling system
boot-strap air cooling system
reduced ambient air cooling system
regenerative air cooli
✅ The correct answer is option D.
A furnace is made of a red brick wall of thickness 0.5 m and conductivity 0.7 W/mK. For the same heat loss and temperature drop, this can be replaced by a layer of diatomite earth of conductivity 0.14 W/mK and thickness
0.5 m
0.1 m
0.2 m
0.5 m
✅ The correct answer is option B.
The amount of heat flow through a body by conduction is
directly proportional to the surface area of the body
directly proportional to the temperature difference on the two faces of the body
inversely proportional to the thickness of the body
all of the above
✅ The correct answer is option D.
The capillary tube is not used in large capacity refrigeration systems because
cost is too high
capacity control is not possible
it is made of copper
required pressure drop
✅ The correct answer is option B.
In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in
parallel flow
counter flow
cross flow
all of these
✅ The correct answer is option D.
The ratio of emissive power of a body to the emissive power of a perfectly black body is called emissivity.
Agree
Disagree
✅ The correct answer is option A.