Answer: 13 Hz
Explanation:
The frequency [tex]f[/tex] of a wave is expressed as:
[tex]f=\frac{1}{T}[/tex]
Where [tex]T[/tex] is the period of the wave
If we are told the period is 0.077 s, then its frequency is:
[tex]f=\frac{1}{0.077 s}[/tex]
[tex]f=12.98 Hz \approx 13 Hz[/tex]
