1415. In case of heat flow by conduction for a cylindrical body with an internal heat source, the nature of temperature distribution is
Linear
Hyperbolic
Parabolic
None of these
✅ The correct answer is option C.
1417. In case of a vertical tube evaporator, with increase in the liquor level, the
Capacity of the evaporator is decreased
Capacity of the evaporator is increased
True temperature drop increases
Both B and C
✅ The correct answer is option A.
1419. In case of parallel flow heat exchanger, the lowest temperature theoretically attainable by the hot fluid is __________ the outlet temperature of the cold fluid.
Equal to
More than
Less than
Either more or less than (depending upon the fluid)
✅ The correct answer is option A.
1421. The absorptivity of a body is equal to its emissivity
At a particular temperature
For circular bodies
Under thermal equilibrium
None of these
✅ The correct answer is option C.
1423. The units of resistance to heat transfer is
J.m⁻².K⁻¹
J.m⁻¹.K⁻¹
W.m⁻².K⁻¹
W⁻¹m²K
✅ The correct answer is option D.
1425. Analogy between mass and heat transfer is not applicable in case of
Same velocity profile or equal eddy diffusivities
Thermal or pressure mass diffusion
Viscous heating or chemical reaction
Both B and C
✅ The correct answer is option D.
1427. The actual temperature drop across the heating surface in an evaporator depends on the
Feed
Depth of liquid over heating surface
Pressure difference between steam chest and vapour space
All of the above
✅ The correct answer is option D.
1430. A steel sphere of radius 0.1 m at 400°K is immersed in an oil at 300°K. If the centre of the sphere reaches 350°K in 20 minutes, how long will it take for a 0.05 m radius steel sphere to reach the same temperature (at the centre) under identical conditions ? Assume that the conductive heat transfer co-efficient is infinitely large.
5 minutes
10 minutes
20 minutes
40 minutes
✅ The correct answer is option A.
1433. Duhring rule is important in solving problems on
Distillation
Crystallisation
Evaporation
Humidification
✅ The correct answer is option C.
1436. The average heat transfer co-efficient over the entire length of the plate (ha) and the local heat transfer co-efficient (hL), in case of heat transfer over a flat plate in lminar zone is related as
Ha = 0.8hL
Ha = 2hL
Ha = hL
Ha= 5hL
✅ The correct answer is option B.