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Phase velocity v­p, and group velocity vg in a waveguide are related to the velocity of light c as:

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  1. vp vg = c2
  2. vp + vg = c
  3.  Constant
  4. vp+ vg = Constant

Answer (Detailed Solution Below)

Option 1 : vp vg = c2
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Detailed Solution

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Phase velocity:

It is the rate at which the phase of the wave propagates in space. Mathematically:

ωc = Cut off frequency

ω = Frequency of operation

Group velocity:

It is the velocity at which the overall envelope of the wave travels.

Multiplying both velocities, we get:

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