$A$ simple harmonic progressive wave is represented by the equation $y = 8\sin 2\pi (0.1x - 2t)$,where $x$ and $y$ are in $cm$ and $t$ is in seconds. At any instant,the phase difference between two particles separated by $2.0 \, cm$ in the $x$-direction is ..... $^o$.

If the speed of the wave shown in the figure is $330 \ m/s$ in the given medium,then the equation of the wave propagating in the positive $x$-direction will be (all quantities are in $M.K.S.$ units).

The equation of a travelling wave is given by $y = 0.5 \sin(20x - 400t)$,where $x$ and $y$ are in meters and $t$ is in seconds. The velocity of the wave is .... $m/s$.

If the frequency of a wave is increased by $25 \%$,then the change in its wavelength is (medium not changed).

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.

For a wave represented by the equation $y = 3 \cos \left( \frac{x}{4} - 10t - \frac{\pi}{2} \right)$,what is the maximum velocity of the particle of the medium?