$A$ progressive sound wave is represented by $y = a \sin(400\pi t - \pi x / 6.85)$,where $x$ is in $m$ and $t$ is in $s$. The frequency of the wave is .... $Hz$.

If a travelling wave is given by $y(x, t) = 0.5 \sin (70.1 x - 10 \pi t)$,where $x$ and $y$ are in metre,the time $t$ is in second,then the frequency of the wave is (in $Hz$)

The rope shown at an instant is carrying a wave travelling towards the right,created by a source vibrating at a frequency $n$. Consider the following statements:
$I.$ The speed of the wave is $4n \times ab$
$II.$ The medium at $a$ will be in the same phase as $d$ after $\frac{4}{3n} \text{ s}$
$III.$ The phase difference between $b$ and $e$ is $\frac{3\pi}{2}$
Which of these statements are correct?

In a simple harmonic wave,the minimum distance between particles in the same phase always having the same speed is ..........

$A$ triangular pulse moving at $2 \ cm/s$ on a rope approaches an end at which it is free to slide on a vertical pole. What is the particle speed at the free end at $\frac{3}{4} \ s$ from the instant shown? (in $cm/s$)

If the wave equation is $y = 0.08 \sin \frac{2\pi}{\lambda} (200t - x)$,then the velocity of the wave will be: