Definition:First Radiation Constant/Also defined as

Definition
The first radiation constant is also seen defined as:
 * $c_1 = 8 \pi h c$

where:
 * $h$ denotes the Planck's constant
 * $c$ denotes the speed of light.

This can be obtained from the conventional definition of first radiation constant by multiplying it by $\dfrac {4 \pi} c$.

Also see

 * Definition:Second Radiation Constant