Select the correct statement about the reflection and refraction of a wave at the interface between medium $1$ and medium $2$.

The displacement of two sinusoidal waves is given by the equations:
$y_1 = 8 \sin(20x - 30t)$
$y_2 = 8 \sin(25x - 40t)$
Then the phase difference between the waves at time $t = 2 \ s$ and distance $x = 5 \ cm$ will be:

In a transverse wave,the distance between a crest and the neighbouring trough at the same instant is $4.0 \, cm$,and the distance between a crest and trough at the same place is $1.0 \, cm$. The next crest appears at the same place after a time interval of $0.4 \, s$. The maximum speed of the vibrating particles in the medium is

The equation of a transverse wave travelling along a string is $y(x, t) = 4.0 \sin(20 \times 10^{-3} x + 600 t) \ mm$,where $x$ is in $mm$ and $t$ is in seconds. The velocity of the wave is:

One end of a long string of linear mass density $8.0 \times 10^{-3} \; kg \; m^{-1}$ is connected to an electrically driven tuning fork of frequency $256 \; Hz$. The other end passes over a pulley and is tied to a pan containing a mass of $90 \; kg$. The pulley end absorbs all the incoming energy so that reflected waves at this end have negligible amplitude. At $t=0$,the left end (fork end) of the string $x=0$ has zero transverse displacement $(y=0)$ and is moving along the positive $y$-direction. The amplitude of the wave is $5.0 \; cm$. Write down the transverse displacement $y$ as a function of $x$ and $t$ that describes the wave on the string.

$A$ pulse on a string is shown in the figure. $P$ is a particle of the string. State which of the following is incorrect.