Blackbody Radiation Formulae
Planck's Law
Planck's Law is used to calculate the spectral radiance of a blackbody at a certain temperature. Despite how complicated the equation looks, it is actually quite simple. The only two variables in the formula are lambda and T, and everything else is a constant. This formula was discovered by Max Planck in 1900, and is the formula used to create blackbody curves by setting a constant temperature, leaving only the wavelength as a variable.
Stefan-Boltzmann Law
This law is used to calculate the total power per unit area of a blackbody at a certain temperature T. This is also the integral of the blackbody curve at T.
This formula can be used to calculate the thermal emission from the human body at room temperature. By plugging both the body and room temperature, then subtracting the value found with room temperature from the value found from the body, and then multiplying by the surface area of an adult human (about 2 m^2), the net power of a human's thermal radiation is about 100 W (Wikipedia).
This formula can be used to calculate the thermal emission from the human body at room temperature. By plugging both the body and room temperature, then subtracting the value found with room temperature from the value found from the body, and then multiplying by the surface area of an adult human (about 2 m^2), the net power of a human's thermal radiation is about 100 W (Wikipedia).
Wien's Displacement Law
This law states that the frequency of the peak of emission is in a linear ratio with the temperature of the black body. Therefore, since wavelength is in an inverse ratio with frequency, the wavelength of the peak emission is in an inverse ratio with the temperature of the black body (Swinburne University).
This law states that the frequency of the peak of emission is in a linear ratio with the temperature of the black body. Therefore, since wavelength is in an inverse ratio with frequency, the wavelength of the peak emission is in an inverse ratio with the temperature of the black body (Swinburne University).