Question

Which of the following expressions is that of a simple harmonic progressive wave?

• A. $ a\,\sin \,\omega t $
• B. $ a\,\sin \,(\omega t)\,\cos \,kx $
• C. $ a\,\sin \,(\omega t-kx)\, $
• D. $ a\cos kx $

Answer 1

Answer: (C)

General equation of wave motion should be represented by
$y=f(a x \pm b t) \text { or } f(a t \pm b x)$
When $y$ is a sine or cosine function such as
$y =a \sin (\omega t-k x) $
or $y =a \cos (\omega t-k x)$
it is called simple harmonic progressive wave.