-----Original Message-----
From: Phys-l [mailto:phys-l-bounces@phys-l.org] On Behalf Of John Denker
Sent: Wednesday, April 02, 2014 2:14 PM
Anyway, here's the example:
a) Consider the black-body spectrum(or almost any spectrum)
in terms of power per unit frequency. Find "the" peak of
"the" spectrum.
b) Now consider the same spectrum in terms of power per unit
wavelength. Find "the" peak of "the" spectrum.
c) Observe that the two peaks do not occur at the same place!
Specifically,
λ_peak < c / f_peak
and
f_peak < c / λ_peak
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As noted in:
"Some paradoxes, errors, and resolutions concerning the spectral
optimization of human vision" by Soffer and Lynch