Unformatted text preview: on Tuesday, November 12, 2013 Aside: bee’s eyes!
humans: 390-750nm human’s
Tuesday, November 12, 2013 bees: 300-650nm Bee’s
view Bees see UV spectrum (small wavelength)
that we cannot see. Flowers evolve to look
especially pretty for the bees, with bullseye targets,
visible in the UV spectrum. human’s
view Light in clear materials
in materials: µ0 → µ 0 → Magnetic permeability
and electric polarizability. If you’ve seen this in Phys 2B, great - if not, don’t
worry about it. We don’t really need much here.
All we need to know is that we again ﬁnd Maxwell’s
equations admits wave solutions, but the velocity of
the wave is modiﬁed by the material:
v=√ Tuesday, November 12, 2013 µ ≡ c/n. Index of refraction n
Light effectively moves slower than c in materials,
because it has to bounce around through an
obstacle course of atoms. Amount of slowing
depends on the material, it’s density etc. Write it
v = c/n ≤ c
Actually, it’s possible to design exotic “metamaterials,”
with negative index of refraction! Pioneered her...
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