A. 1.65 x 10^-10 m
Explanations:The relationship between the speed(v), frequency(f), and wavelength(λ) of an electromagnetic wave is given as:
v = λf
From the question:
[tex]\begin{gathered} v\text{ = 3}\times10^8m\text{ /s} \\ f\text{ = 1.82}\times10^{18}Hz \end{gathered}[/tex]Substituting the values of v and f into the equation v = λf
[tex]\begin{gathered} 3\times10^8=\lambda\times(1.82\times10^{18}) \\ \lambda\text{ = }\frac{3\times10^8}{1.82\times10^{18}} \\ \lambda\text{ = }1.65\text{ }\times10^{-10}m \end{gathered}[/tex]Therefore, the wavelength of the electromagnetic wave is 1.65 x 10^-10 m
