Question 182: EM waves

Question

An electromagnetic wave of frequency 5 GHz, is travelling in a medium whose relative electric permittivity and relative magnetic permeability both are 2. Its velocity in this medium is ____________ $$	imes$$ 107 m/s.

Accepted Answer

Given, $$\mu$$
r
= $$\varepsilon $$
r
= 2
where, $$\mu$$
r
is relative permeability, $$\varepsilon $$
r
is relative permittivity.
Speed of electromagnetic wave v is given by
$$v = {c \over n}$$
where, n = refractive index = $$\sqrt {{\mu _r}{\varepsilon _r}}  = \sqrt 4  = 2$$
$$ \Rightarrow v = {{3 	imes {{10}^8}} \over 2}$$ = 15 $$	imes$$ 10
7
m/s
$$\because$$ x $$	imes$$ 10
7
= 15 $$	imes$$ 10
7
$$\Rightarrow$$ x = 15

EM waves

An electromagnetic wave of frequency 5 GHz, is travelling in a medium whose relative electric permittivity and relative magnetic permeability both are 2. Its velocity in this medium is ____________ $\times$ 107 m/s.

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