The speed of an electromagnetic wave in a medium of dielectric constant 2.25 and relative permeability 4 is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $10^8ms^{-1}$
Speed of an electromagnetic wave in a medium, $v=\frac{c}{\sqrt{μ_rε_r}}$
where,
$v$ = speed of wave in that medium
$c$ = speed of light
$μ_r$ = Relative permittivity of medium
$ε_r$ =Relative permittivity
$v=\frac{3×10^8}{\sqrt{4×2.25}}=\frac{3×10^8}{3}$
$μ_r=4$ [given]
$ε_r=2.25$ [given]
$v=10^8m/s$