The transfer of heat in case of radiation takes place by means of
A.Heated particles of the medium
B.Electromagnetic waves
C.Thermal energy of the source
D.None of the above
Category: Heat Transfer Mcqs
Which of the following material has thermal conductivity closest to silver?
A.Copper
B.Brass
C.Aluminium
D.Steel
The surface temperatures of a flat wall are 650?C and 450?C respectively and the thermal conductivity of the wall material is 0.30 kcal/m-hr-?C. The heat flux for a wall of 20 cm thickness will be
A.300 kcal/m2-hr
B.120 kcal/m2-hr
C.60 kcal/m2-hr
D.450 kcal/m2-hr
E.600 kcal/m2-hr
A non-dimensional number generally associated with natural convection heat transfer is
A.Peclet number
B.Nusselt number
C.Prandtl number
D.Grashof number
E.Weber number
The emissivity of a body will be equal to absorptivity when
A.Body is at low temperature
B.Body is at high temperature
C.Temperature of body is rising
D.Temperature of body is falling
E.Body is in thermal equilibrium
A prototype is
A.a geometrical similar model on reduced scale
B.a dynamically similar model on reduced scale
C.a kinematically similar model on reduced scale
D.a full size structure employed in actual engineering design
The ratio of the actual vapour pressure to the pressure of saturated vapour at the prevailing dry bulb temperature is known as
A.Specific humidity
B.Vapour humidity
C.Relative humidity
D.Humidity ratio
E.Humidity
The lower temperature limit for mercury thermometer is
A.0?C
B.0?F
C.? 39?F
D.100?C
E.Absolute zero
Which of the following has higher thermal conductivity as compared to the remaining?
A.Oxygen
B.Air
C.Hydrogen
D.Water
