- . . . Questions:1
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Take n=1.5 as the index of refraction typical of glass.
You can look up electric permeabilities in Table 4.2 on page 180,
magnetic susceptibilities in Table 6.1 on page 275
and resistivities in Table 7.1 on page 286.
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- . . . have2
- It is actually rather difficult to measure
the permittivity of a metal. (Think about it!)
Mostly we just assume
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- . . . water.3
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Your calculation should yield a skin depth of about
1.2 x 104 m for pure water. (No points for just the answer!)
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- . . . 12 km).4
- The
darkness of the deep ocean is partly due to particulates
in the water (scattering the light), and partly because
salt water is a much better conductor!
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- . . . reflection,5
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Our present Provost, Lorne Whitehead, had an idea to build hollow-core
light pipes using total internal reflection when he was a graduate student
in our Department; he patented the idea, formed a company called
(you guessed it) TIR Ltd. and built it up over a decade into a
model of Canadian entrepreneurship, after which he came back to UBC
as a Physics Professor, and the rest is, as they say, history.
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- . . . 2.6
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The evanescent fields can be detected by placing a second interface
a short distance into medium 2;
in a close analogue to quantum mechanical tunneling,
the wave crosses the gap and reassembles beyond it.
See F. Albiol, S. Navas and M.V. Andres,
Am. J. Phys. 61, 165 (1993).
[You might wonder whether medium 3 needs to have n3 > n2
for this to work, or if any meaningful interface will do,
or if there is a more subtle criterion.
But you don't have to work that out for this problem!]
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