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

The phase difference corresponding to a path difference of $x$ is

For a transverse wave travelling along a straight line,the distance between two peaks (crests) is $5 \, m$,while the distance between one crest and one trough is $1.5 \, m$. The possible wavelengths (in $m$) of the waves are

$A$ progressive wave of frequency $400 \ Hz$ is travelling with a velocity $336 \ m/s$. How far apart are the two points which are $60^{\circ}$ out of phase (in $m$)?

The distance between two consecutive crests in a wave train produced in a string is $5 \ cm$. If $2$ complete waves pass through any point per second,the velocity of the wave is ..... $cm/sec$.

The speed of a wave in a certain medium is $960 \,m/s$. If $900$ waves pass over a certain point of the medium in half a minute, the wavelength of the wave is (in $\,m$)