Answer:
3.82 ms
Explanation:
The period of a wave is equal to the reciprocal of the frequency:
[tex]T=\frac{1}{f}[/tex]
where f is the frequency.
In this problem, f = 262 Hz, so the period if this sound wave is
[tex]T=\frac{1}{262 Hz}=3.82\cdot 10^{-3} s=3.82ms[/tex]