Question

A plane progressive wave is given by $y=2\cos 6.284(330t-x)$. What is period of the wave?

• A. $\frac{1}{330}s$
• B. $2\pi \times 330s$
• C. ${(2\pi \times 330)}^{-1}s$
• D. $\frac{6.284}{330}s$

Answer 1

The correct option is A $\frac{1}{330}s$

We have the progressive wave given by:

$y=2\cos 6.284(330t-x)$

$y=2\cos 2\pi (330t-x)$

$y=2\cos (2\pi \times 330t-2\pi x)$

On comparing the given progressive equation with $y=Acos(wt-kx)$,

we get, $\omega =2\pi \times 330$ and time period $T=\frac{2\pi }{\omega }=\frac{1}{330}s$