The unit of Stefan Boltzmann constant is ____________________?
A. watt/cm2 °K
B. watt/cm4 °K
C. watt2/cm °K4
D. watt/cm2 °K4
E. watt/cm2 °K2
Month: January 2019
Log mean temperature difference in case of counter flow compared to parallel flow will be________________?
Log mean temperature difference in case of counter flow compared to parallel flow will be________________?
A. same
B. more
C. less
D. depends on other factors
E. none of the above
According to Stefan-Boltzmann law, ideal radiators emit radiant energy at a rate proportional to___________________?
According to Stefan-Boltzmann law, ideal radiators emit radiant energy at a rate proportional to___________________?
A. absolute temperature
B. square of temperature
C. fourth power of absolute temperature
D. fourth power of temperature
E. cube of absolute temperature
In free con-vection heat transfer, Nusselt number is function of________________?
In free con-vection heat transfer, Nusselt number is function of________________?
A. Grashoff no. and Reynold no
B. Grashoff no and Prandtl no.
C. Prandtl no. and Reynold no
D. Grashoff no., Prandtl no and Reynold no
E. none of the above
Which of the following property of air does not increase with rise in temperature ________________?
Which of the following property of air does not increase with rise in temperature ________________?
A. thermal conductivity
B. thermal diffusivity
C. density
D. dynamic viscosity
E. kuiematic viscosity
The energy distribution of an ideal reflector at higher temperatures is largely in the range of ___________________?
The energy distribution of an ideal reflector at higher temperatures is largely in the range of ___________________?
A. shorter wavelength
B. longer wavelength
C. remains same at all wavelengths
D. wavelength has nothing to do with it
E. none of the above
The value of Prandtl number for air is about _______________________?
The value of Prandtl number for air is about _______________________?
A. 0.1
B. 0.3
C. 0.7
D. 1.7
E. 10.5
Total emissivity of polished silver compared to black body is___________________?
Total emissivity of polished silver compared to black body is___________________?
A. same
B. higher
C. more or less same
D. very much lower
E. very much higher
The value of the wavelength for maximum emissive power is given by ___________________?
The value of the wavelength for maximum emissive power is given by ___________________?
A. Wien’s law
B. Planck’s law
C. Stefan’s law
D. Fourier’s law
E. Kirchhoff’s law
The unit of overall coefficient of heat transfer is___________________?
The unit of overall coefficient of heat transfer is___________________?
A. kcal/m2
B. kcal/hr °C
C. kcal/m2 hr °C
D. kacl/m hr °C
E. kcal/m3 hr °C