Thermal conductivity of air at room temperature is approximately
A.0.002 kcal/m-hr-?C
B.0.02 kcal/m-hr-?C
C.0.2 kcal/m-hr-?C
D.2.0 kcal/m-hr-?C
E.20.0 kcal/m-hr-?C
Category: Heat Transfer Mcqs
A vapour containing liquid particles to the extent of 50% by the volume is known as
A.Saturated liquid
B.Super saturated liwuid
C.Wet vapour
D.Saturate vapour
E.Superheated vapour
The dimensions of specific heat are
A.LT?2
B.LT-1?-1
C.LT-2?
D.LT-2?-1
Which insulating material is suitable for low temperature applications?
A.Cork
B.Asbestos paper
C.Diatomaceous earth
D.85% magnesia
E.Fused alumina bricks
Which is not the assumption in Fourier’s equation of heat conduction?
A.Homogeneous substance
B.Steady heat flow
C.Constant temperature difference
D.Thermal conductivity independent of temperature
E.Uniform area of cross-section
Emissivity and absorptivity of a surface are equal for radiation
A.in ultraviolet region
B.infrared region
C.with equal temperature and wavelength
D.in radio frequency range
Which of the following can be used to measure a temperature around -50?C?
A.Mercury thermometer
B.Alcohol thermometer
C.Thermocouple
D.Platinum resistance thermometer
Which of the following has the highest value of the thermal conductivity
A.Clay
B.Wood
C.Asbestos
D.Refractory brick
E.Nichrome
In which case does the thermal conductivity increase from left to right?
A.Aluminium, copper, silver
B.Silver, copper, aluminium
C.Copper, silver, aluminium
D.Aluminium, silver, copper
A dimensionless number which is the ratio of mass heat flow rate to the heat flow rate by conduction under a unit temperature gradient and through a thickness L is known as
A.Peclet number
B.Nusselt number
C.Grashof number
D.Weber number
E.Prandtl number
