For an electromagnetic wave, the basic relationship between frequency, wavelength and speed of the wave (which is the speed of light) is
[tex]\lambda= \frac{c}{f} [/tex]
where
c is the speed of light
f is the frequency of the wave
[tex]\lambda[/tex] is the wavelength
Plugging the numbers given by the problem into the equation, we find the wavelength:
[tex]\lambda= \frac{c}{f}= \frac{3 \cdot 10^8 m/s}{3.0 \cdot 10^9 Hz}=0.1 m [/tex]
