The equation of a travelling wave is $y = 60 \cos (1800t - 6x)$,where $y$ is in microns,$t$ is in seconds,and $x$ is in metres. The ratio of maximum particle velocity to the velocity of wave propagation is:

Given below are some functions of $x$ and $t$ to represent the displacement of an elastic wave.
$(i) \, y = 5 \cos (4x) \sin (20t)$
$(ii) \, y = 4 \sin (5x - t/2) + 3 \cos (5x - t/2)$
$(iii) \, y = 10 \cos (252\pi t) \cos (250\pi t)$
$(iv) \, y = 100 \cos (100\pi t + 0.5x)$
State which of these represent:
$(a)$ a travelling wave along $-x$ direction
$(b)$ a stationary wave
$(c)$ beats
$(d)$ a travelling wave along $+x$ direction.
Give reasons for your answers.

$A$ travelling harmonic wave is represented by the equation $y(x, t) = 10^{-3} \sin(50t + 2x)$,where $x$ and $y$ are in meters and $t$ is in seconds. Which of the following is a correct statement about the wave?

$A$ wave is given by $y=5 \times 10^{-3} \sin \left(12.5 \pi x - \frac{\pi}{2} t\right)$. Then its wavelength and time period are respectively ($y$ and $x$ are in metres and $t$ is in seconds).

What is the phase difference between two successive crests in a wave?

The transverse displacement $y(x, t)$ of a wave on a string is given by $y(x, t) = e^{-(ax^2 + bt^2 + 2\sqrt{ab}xt)}$. This represents a