Explanation:
Given that,
The frequency of microwaves, [tex]f=9\times 10^9\ Hz[/tex]
The time period of the wave is :
[tex]t=\dfrac{1}{f}\\\\t=\dfrac{1}{9\times 10^9}\\\\t=1.1\times 10^{-10}\ s[/tex]
Let [tex]\lambda[/tex] is the wavelength of the wave. We know that,
[tex]v=f\lambda\\\\\lambda=\dfrac{v}{f}[/tex]
Put all the values,
[tex]\lambda=\dfrac{3\times 10^8}{9\times 10^{9}}\\\\\lambda=0.03\ m[/tex]
Hence, this is the required solution.