d²T/dZ² > 0
d²T/dZ² = 0
d²T/dZ² < 0
dT/dZ = 0
✅ The correct answer is option B.
Heat Transfer MCQs
A black body does not __________ radiation.
Absorb or emit
Refract
Reflect
Both B & C
✅ The correct answer is option D.
Stefen’s block body radiation law can also be derived from __________ law.
Kirchoffs
Planck’s
Fourier’s
None of these
✅ The correct answer is option B.
What is the geometric mean of two heat transfer areas A₁ and A₂ ?
√(A₁ . A₂)
√(A₁ + A₂)
1/2 √(A₁ . A₂)
2 √(A₁ . A₂)
✅ The correct answer is option A.
The rate of heat transfer is a product of overall heat transfer co-efficient, the difference in temperature and the
Heating volume
Heat transfer area
Nusselt number
None of these
✅ The correct answer is option B.
In forced convection, the Nusselt number is a function of
Re and Pr
Re and Gr
Pr and Gr
Re and Sc
✅ The correct answer is option A.
In which mode of heat transfer, the Biot number is important?
Transient heat conduction
Natural convection
Forced convection
Radiation
✅ The correct answer is option A.
Viscous & heat sensitive liquids are concentrated in __________ evaporators.
Open pan
Long tube
Agitated film
None of these
✅ The correct answer is option C.
A black body when hot, emits heat radiation of __________ wavelengths.
Small
Large
All
One fixed
✅ The correct answer is option C.
Steam economy in case of a triple effect evaporator will be
1
< 1
> 1
Between 0 and 1
✅ The correct answer is option C.