Maximum resistance in the series
Sum of all resistances
Average of all resistances
Minimum resistance presents in the series
✅ The correct answer is option B.
Heat Transfer MCQs
The purpose of providing expansion bellows in the shell of tubular exchanger is to
Increase the heating load
Impart structural strength
Account for the uneven expansion of shell and tube bundles
Facilitate increase of shell length, if needed
✅ The correct answer is option C.
200 kg of solids (on dry basis) is subjected to a drying process for a period of 5000 seconds. The drying occurs in the constant rate period with the drying rate as, Nc = 0.5 x 10⁻³ kg/m².s. The initial moisture content of the solid is 0.2 kg moisture/kg dry solid. The interfacial area available for drying is 4 m²/1000 kg of dry solid. The moisture content at the end of the drying period is (in kg moisture/kg dry solid)
0.5
0.05
0.1
0.15
✅ The correct answer is option C.
A wall has two layers of materials A and B; each made of a different material. Both the layers have the same thickness. The thermal conductivity of materialA is twice that of B. Under the equilibrium, the temperature difference across the wall is 36°C. The temperature difference across the layer A is __________ °C.
6
12
18
24
✅ The correct answer is option B.
Which of the following parameters is increased by use of finned tube in a multipass shell and tube heat exchanger?
Tube side pressure drop and the heat transfer rate
Convective heat transfer co-efficient
Effective tube surface area for convective heat transfer
All of the above
✅ The correct answer is option D.
__________ paint has the minimum absorption co-efficient.
Black
White lead
Grey
Light cream
✅ The correct answer is option B.
Nusselt number is the ratio of the
Temperature gradient of the wall to that across the entire pipe
Temperature difference to the temperature gradient at the wall
Heat flux at the wall to that across the entire pipe
None of these
✅ The correct answer is option C.
The thermal efficiency of a reversible heat engine operating between two given thermal reservoirs is 0.4. The device is used either as a refrigerator or as a heat pump between the same reservoirs. Then the coefficient of performance as a refrigerator (COP)R and the co-efficient of performance as a heat pump (COP)HP are
(COP)R = (COP)HP = 0.6
(COP)R = 2.5; (COP)HP = 1.5
(COP)R = 1.5; (COP)HP = 2.5
(COP)R = (COP)HP = 2.5
✅ The correct answer is option C.
Which is the most suitable for cold viscous feed?
Forward feed
Backward feed
Mixed feed
Parallel feed
✅ The correct answer is option B.
In case of evaporators, liquid entrainment results primarily due to
High vacuum in the evaporator
High evaporation rate
Foaming of the solution
High heat transfer rate
✅ The correct answer is option C.