The figure shows a sinusoidal wave at a given instant. Which points are in the same phase?

The equation of a progressive wave is $y = 4 \sin(4 \pi t - 0.04 x + \pi / 3)$,where $x$ is in meters and $t$ is in seconds. The velocity of the wave is:

The equation of a transverse wave is given by $y = 100 \sin \pi (0.04z - 2t)$,where $y$ and $z$ are in $cm$ and $t$ is in seconds. The frequency of the wave in $Hz$ is

The equation of a wave is given by (all quantities expressed in $M.K.S.$ units) $Y = 5 \sin(10\pi t - 0.1\pi x)$ along the $x$-axis. The phase difference between two points separated by a distance of $10 \ m$ along the $x$-axis is:

The distance between two consecutive points with a phase difference of $60^{\circ}$ in a wave of frequency $500 \text{ Hz}$ is $0.6 \text{ m}$. The velocity with which the wave is travelling is: (in $\text{ km/s}$)

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