Question

Which of the following represents a standing wave?

• A. $y=A \sin (\omega t-k x)$
• B. $y=A e^{-b x} \sin (\omega t-k x+\alpha)$
• C. $y=A \sin k x \sin (\omega t-\theta)$
• D. $y=(a x+b) \sin (\omega t-k x)$

Answer 1

Answer: (C)

In a standing wave, the amplitude is an oscillating function of $x$ in :
$y=A \sin k x \sin (\omega t+\theta)$
$A \sin k x$ represents the amplitude and is of the correct form to be a standing wave.
$y=3 \sin \frac{\pi x}{3} \cos 40 \pi t$