Roy Lewallen wrote:
Thanks, Jim for the correction. I had failed to notice that the graph
scale was normalized to wavelength. I stand corrected.

Roy Lewallen, W7EL

To be honest, I'm not sure which one is appropriate to integrate. In
theory, if you're integrating between two limits you'd use the
expression that matches how the limits are specified..

That is, if you wanted to get the energy between 350 and 600 nm, then
you'd use the energy/nm

OTOH, if you wanted to integrate between 470 THz and 800THz, you'd use
energy/Hz.

they "should" come out with the same answer (especially in the limit of
actual integration with respect to d(nu) or d(lambda)).

It's probably only when you do a rough and ready numerical integration
(or do it by eye off the graph) that it makes a difference.

Actually, it's kind of interesting that you brought it up, because, like
you, I'd always seen the W/nm with a linear scale in nm graphs...