- #1

tony873004

Science Advisor

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**Plank's law -- my computer is having trouble with the formula**

[tex]f_\lambda \left( T \right) = \frac{{2\pi hc^2 /\lambda ^5 }}{{\exp \left( {\frac{{hc}}{{\lambda kT}}} \right) - 1}}

[/tex]

I'm guessing this thing wants wavelength in meters. So for a temperature of 5600 K and a wavelength of 0.5 um (5e-7 m), the part that I'm using as the exponent for e, [tex]{\frac{{hc}}{{\lambda kT}}}

[/tex] comes out to (6.626068e-24*2.99792458e8/(5e-7*1.3806503e-23*5600)) =51384823425.8871.

And e^51384823425.8871 is not a number my computer can calculate.

How can I use this formula?