Question

The equation of a longitudinal wave is represented as $y=20\cos \pi \left(50t-x\right).$ its wavelength is

• A. $5m$
• B. $2m$
• C. $50m$
• D. $20m$

Answer 1

Answer: (B)

$2m$

The equation of a longitudinal wave is represented by

$y=20cos\pi (50t-x)=20cos(50\pi t-\pi x)$

from the above equation

$k=\pi$

$\frac{2\pi }{\lambda }=\pi$

$\lambda =2cm$

The correct option is B.