The electric field vector of a plane electromagnetic wave oscillates sinusoidally at a frequency of $4.5 × 10^{10} Hz$ in a medium with permittivity to and permeability $μ_0$. The wavelength of the wave is

$6.67 × 10^{-3} m$

The correct answer is Option (3) → $6.67 × 10^{-3} m$

Given:

Frequency, $f = 4.5 \times 10^{10}\,Hz$

Medium: free space ($\varepsilon = \varepsilon_0$, $\mu = \mu_0$)

Speed of light, $c = \frac{1}{\sqrt{\mu_0 \varepsilon_0}} = 3 \times 10^{8}\,m/s$

Wavelength, $λ = \frac{c}{f}$

$λ = \frac{3 \times 10^{8}}{4.5 \times 10^{10}}$

$λ = 6.67 \times 10^{-3}\,m$

Final Answer: $λ = 6.7 \times 10^{-3}\,m$