A perfect black body is the one which
A.Absorbs all incident radiation
B.Reflects all incident radiation
C.Absorbs most of the incident radiation
D.Is coated with lamp black
Category: Heat Transfer Mcqs
A steam pipe is to be insulated by two insulating materials put over each other. For best results
A.Better matt. Over pipe and inferior over it
B.Inferior matt. Over pipe and better over it
C.Can be in any order
D.None of the above
The nature of flow of a fluid inside a tube i.e., whether it is turbulent or laminar, is ascertained by
A.Flow velocity
B.Tube size
C.Surface conditions
D.Viscosity of fluid
E.Reynolds number
At all wavelengths and temperatures the monochromatic emissivity of a white body is equal to
A.Zero
B.0.1 to 0.5
C.0.5
D.0.5 to 1
E.Unity
The material preferred for the fabrication of fruit juice concentrator is
A.Cast iron
B.Mild steel sheet
C.Stainless steel sheet
D.Copper
E.Brass
The wavelength for maximum emissive power is given by
A.Planck’s law
B.Fourier’s law
C.Wein’s law
D.Stefan Boltzman’s law
E.Kirchhoff’s law
Gases have poor
A.Reflectivity
B.Absorptivity
C.Transmissivity
D.Absorptivity + transmissivity
E.Reflectivity + absorptivity
Fouling factor
A.Is dimensionless
B.Measures the heat transfer efficiency
C.Is virtually a factor of safety in heat exchanger design
D.Is used when a liquid exchanges heat with a gas
E.Is used only in case of Newtonian fluids
