For a blackbody at thermodynamic temperature T, the radiancy R over a range of frequencies between nu and nu + dnu is given by
R = 2 pi nu2 k T/c2.
Compare Planck radiation law; see ultraviolet catastrophe.
1.22 lambda/d.
n1 sin theta = n2 sin phi.
The rule is also applicable in several practical applications, such as determining which way to turn a screw, etc. There is also a left-hand rule, which exhibits opposite chirality.
For the transition between an electron in orbital m to one in orbital n (or the reverse), the wavelength lambda involved is given by
1/lambda = R (1/m2 - 1/n2).