Explain whens displacement taw Explain kirchhoffs law on rad

Explain when\'s displacement taw Explain kirchhoff\'s law on radiation What is the relation between the absorptive, reflectivity, and transmissivity. Explain the Stefan-Boltzmann law in radiation Explain the planck distribution, or planck\'s law Draw the velocity profile (a) in the momentum boundary layer and temperature profile (b) in the thermal boundary layer in free convection in vertical plate, as shown in figure below. Wall temperature is higher than the surrounding fluid temperature. (i)Explain the Boussinesq approximation with approximation relation of density, volumetric thermal expansion coefficient, and temperature, (ii) using the approximation, how is the x-momentum equation changed? Write the relation of Laminar thermal entry length and Turbulent thermal entry length respectively, in terms of L, D, Re, Pr

Solution

2. Krichhhoffs law refers to wavelength specific radiative emission and absorption by a material bopdy in thermodyanmic eqilibrium including radioactive exchange equillibrium.

A body at temprature \" T \" radiates electromagnetic energy. A perfect black body in thermodyanamic equilibrium absorbs all light that strikes it and radates energy according to a unique law of radiative emissive power to temprature T, universal to all perfect black bodies.

For a body of any artbitary material emitting and absorbing thermal electromagnetic radiation at energy wavelength in thermodynamic equillibrium, the ratio of its emissive power to ts dimensionless co-efficient of absorption is equal to a universal function onlyof raiative wavelength. That universal function describes the perfect black body emissive power.