The speed of an electromagnetic wave in a medium of dielectric constant 2.25 and relative permeability 4 is:

$10^8ms^{-1}$

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]

$v=10^8m/s$