# Stefan-Boltzmann Constant

Written by Jerry Ratzlaff on . Posted in Classical Mechanics

Stefan-Boltzmann constant, abbreviated as $$\sigma$$  (Greek symbol sigma), is the total intensity ratiated over all wavelength increases as the temperature increases.

## Stefan-Boltzmann Constant formula

 $$\large{ \sigma = \frac{ 2\; \pi^5 \; k_b^4 }{ 15 \; h^3 \; c^2 } }$$

### Where:

 Units English SI $$\large{ \sigma }$$  (Greek symbol sigma) = Stefan-Boltzmann constant $$\large{\frac{Btu}{ft^2\;hr\; R^4}}$$ $$\large{ \frac{W}{m^2-K^4} }$$ $$\large{ k_b }$$ = Boltzmann constant $$\large{ \frac{lbm-ft^2}{sec^2} }$$ $$\large{ \frac{kJ}{molecule-K} }$$ $$\large{ \pi }$$ = Pi $$\large{3.141 592 653 ...}$$ $$\large{ h }$$ = Planck's constant $$\large{ \frac{lbf-ft}{sec} }$$ $$\large{ J-s }$$ $$\large{ c }$$ = speed of light in vacuum $$\large{ \frac{ft}{sec} }$$ $$\large{ \frac{m}{s} }$$

## Stefan-Boltzmann Constant

 $$\large{ \sigma = 1.713441 \;x\; 10^{-9} \frac{Btu}{ft^2 \; hr \; R^4}}$$ $$\large{ \sigma = 5.670374419 \;x\;10^{-8} \;\frac{W}{m^2 \; K^4} }$$