Answer:
L= 0.75m
Explanation:
To develop the exercise we need to use the Frequency equation, so,
[tex]f=\frac{c}{\lambda}[/tex]
[tex]f= \frac{c}{2L}[/tex]
[tex]L= \frac{c}{2f}[/tex]
[tex]L = \frac{3*10^8m/s}{2*(2.04*10^8Hz)}[/tex]
[tex]L= 0.75m[/tex]