Question

Which of the following equations represents a travelling wave?

• A. $y=3\sin \left(\pi t\right)$
• B. $y=3\cos \left(5x\right)$
• C. $y=3\sin \left(\varphi \right)$
• D. $y=3\sin (\pi t-5x)$

Answer 1

The correct option is D $y=3\sin (\pi t-5x)$

We know that any function of the form $f(t\pm \frac{x}{v})$ represents a travelling wave.
Here, $y=3\sin (\pi t-5x)$ is in the form $f(t-\frac{x}{v})$. Thus, it represents a wave.

Hence, option (d) is the correct answer.