I'm told the spectral radiance of a source is in the following units(adsbygoogle = window.adsbygoogle || []).push({});

W

----------------

cm^2 * sr * nm

And I try to use this to figure the spectral output of monochromator (in W), but I can't seem to cancel out the units. I multiply the spectral radiance by four other terms

slit width (cm)

slit height (cm)

solid angle, using a quick "f-number" equation (sr)

and then the transmission optics factor, which I assume could be unitless but I could be wrong.

Anyways, anybody know why I get W/nm instead of W? Or is it really just W?

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# Homework Help: Spectral Radiance and it's Units

**Physics Forums | Science Articles, Homework Help, Discussion**