Question

Use F = 1/T as your basis:

Answer 1

• Time Period=T=2.5×10^{-3}s

Now

Frequency:-

$\\ \rm\rightarrowtail \nu=\dfrac{1}{T}$

$\\ \rm\rightarrowtail \nu=\dfrac{1}{2.5\times 10^{-3}}$

$\\ \rm\rightarrowtail \nu=0.4\times 10^{3}$

$\\ \rm\rightarrowtail \nu=400Hz$