Question

Electromagnetic wave travel in medium at a speed of `2.0xx10^8ms^-1`. The relative permeability of the medium is 1.0. Find the relative permitivity.

Answer 1

Here `v=2xx10^8ms^-1, mu_r=1, c=3xx10^8ms^-1`
Speed of e.m. wave in a medium is given by
`(1)/(sqrt(muin)) =(1)/(sqrt(mu_(0)mu_(r)(in_(0)in_(r)))) =(1)/(sqrt(mu_(0)in_(0))) xx (1)/(sqrt(mu_(r)mu_(r)))` or `in_(r)=(c^(2))/(v^(2)mu_(r))= ((3xx10^(8))^(2))/((2xx10^(8))^(2)xx1) =2.25`