Question

A plane progressive wave is given by \( y = 2 \cos 2\pi(330t - x) \, \text{m} \). The frequency of the wave is:

• A. 165 Hz
• B. 330 Hz
• C. 660 Hz
• D. 340 Hz

Answer 1

The Correct Option is B

The general form of a plane progressive wave is:
\[y = A \cos(\omega t - kx).\]
Comparing with the given equation:
\[y = 2 \cos 2\pi (330 t - x),\]
we identify:
\[\omega = 2\pi \times 330.\]
The angular frequency \(\omega\) is related to the frequency \(f\) by:
\[\omega = 2\pi f \implies 2\pi f = 2\pi \times 330.\]
Thus:
\[f = 330 \, \text{Hz}.\]