Boiling point
Dynamic viscosity
Kinematic viscosity
Density
✅ The correct answer is option A.
Engineering MCQs
In evaporators, lowering the feed temperature
Increases the heating area required
Reduces the economy
Both A and B
Decreases the heating area required
✅ The correct answer is option C.
If all the conditions and dimensions are same, then the ratio of velocity through the tubes of a double pass heat exchanger to that through the single pass heat exchanger is
1
2
1-Feb
4
✅ The correct answer is option B.
The inner wall of a furnace is at a temperature of 700°C. The composite wall is made of two substances, 10 and 20 cm thick with thermal conductivities of 0.05 and 0.1 W.m-1.°C-1 respectively. The ambient air is at 30°C and the heat transfer co-efficient between the outer surface of wall and air is 20 W.m⁻².°C-1. The rate of heat loss from the outer surface in W.m-2is
165.4
167.5
172.5
175
✅ The correct answer is option A.
The thermal radiative flux from a surface of emissivity = 0.4 is 22.68 kW/m². The approximate surface temperature (K) is (Stefan-Boltzman constant = 5.67xl0⁻⁸ W/m².K⁴)
1000
727
800
1200
✅ The correct answer is option A.
Heat transfer by radiation between two bodies at T₁ & T₂ and in an ambient temperature of Ta°C depends on
T₁ – T₂
T₁ – Ta
T₂ – Ta
None of these
✅ The correct answer is option D.
In case of a multipass shell and tube heat exchanger, the temperature drop in the fluid
Is inversely proportional to the resistance across which the drop occurs
And the wall are proportional to individual resistances
And the wall is not related
None of these
✅ The correct answer is option B.
In a 1-1 cocurrent heat exchanger, if the tube side fluid outlet temperature is equal to the shell side fluid outlet temperature, then the LMTD is
∞
0
Equal to the difference between hot and cold fluids inlet temperature
Equal to the difference between hot fluid inlet temperature and cold fluid outlet temperature
✅ The correct answer is option B.
h.D/K is called the __________ number.
Nusselt
Peclet
Rayleigh
Grashoff
✅ The correct answer is option A.
For the same heat transfer area and the terminal conditions, the ratio of the capacities of a single effect evaporator to a triple effect evaporator is
3
0.33
1
1.33
✅ The correct answer is option C.