91. For a cold dilute feed to produce thick viscous liquor, backward feeding as compared to forward feeding results in
Increased economy
Decreased economy
Lower capacity
No effect on economy
✅ The correct answer is option A.
Heat Transfer MCQs
92. Temperature profile in steady state heat transfer is
Asymptotic
Hyperbolic
Parabolic
Linear
✅ The correct answer is option D.
93. Absorptivity of a perfect black body is unity. Which of the following has maximum absorptivity?
Aluminium foil
Refractory bricks
Iron plate
Coke breeze
✅ The correct answer is option D.
94. The Fourier number (defined as a.t/L²) is used in the analysis of problem involving heat transfer by
Forced convection
Natural convection
Transient conduction
Steady state conduction
✅ The correct answer is option C.
95. Thermal diffusivity is the most important in heat transfer by
Conduction
Radiation
Condensation
Natural convection
✅ The correct answer is option A.
96. The film thickness for laminar film condensation on vertical surface __________ from top to bottom.
Cummulatively increases
Cummulatively decreases
Remains constant
And the surface conductance increase
✅ The correct answer is option A.
97. The range of electromagnetic spectrum important in heat transfer by radiation is __________ microns.
0.38-0.78
0.5-50
100-1000
May-50
✅ The correct answer is option B.
98. The Graetz number is concerned with the
Mass transfer between a gas and a liquid
Absorption with chemical reaction
Heat transfer in turbulent flow
Heat transfer in laminar flow
✅ The correct answer is option D.
99. In SI units, thermal conductivity is expressed in
Watt/m.°K
Watt/m². °K
Watt/m². °K
Watt/m4. °K
✅ The correct answer is option A.
100. The non-dimensional temperature gradient in a liquid at the wall of a pipe is the
Heat flux
Nusselt number
Prandtl number
Schmidt number
✅ The correct answer is option A.