Verified Answer :

To calculate this we will use the light equation:
\(c=\)λ\(*f\)

We have Frequency \(f=9.4* 10^{9}Hz\).
We know that speed of light in vacuum is \(c =3.8* 10^{8} m/s\).
Since a unit of speed of light is m/s, we can change the unit of frequency Hz to 1/s, since Hz means cycles per second (f=1/T).

So:
\(f=9.4* 10^{9}1/s\)
\(c =3.8* 10^{8} m/s\)

\(c=\)λ\(*f\)
⇒ λ\(= \frac{c}{f}\)
⇒ λ\(= \frac{3.8* 10^{8}}{9.4* 10^{9}}\)
⇒ λ\(=0.04 m\)