Q159 / 160 · WBJEE 2012 · Physics
A progressive wave moving along $x$ -axis is represented by $y=A \sin \left[\frac{2 \pi}{\lambda}(v t-x)\right]$ The
wavelength $(\lambda)$ at which the maximum particle velocity is 3 times the wave velocity is
- A$\frac{\mathrm{A}}{A}$
- B$2 \mathrm{A}(3 \pi)$
- C$\left(\frac{3}{4}\right) \pi A$
- Correct answerD$(2 / 3) \pi A$
Solution
$y=A \sin \left[\frac{2 \pi}{\lambda}(v t-x)\right]$
$v=\frac{2 \pi}{\lambda} V A$
$$
\begin{aligned}
\left(v_{p}\right)_{\max } &=3 v \\
\lambda &=\frac{2 \pi}{3} A
\end{aligned}
$$
Hence, the correct answer is option: 'D'.