Which of the following waves has the largest wave speed?

$A$ wave on a string is travelling and the displacement of particles on it is given by $x = A \sin (2t - 0.1x)$. Then the wavelength of the wave is

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

$A$ wave is represented by $x = 4 \cos \left(8t - \frac{y}{2}\right)$,where $x$ and $y$ are in $m$ and $t$ is in $s$. The frequency of the wave (in $s^{-1}$) is .........

When a wave travels in a medium,the particle displacement is given by $y(x, t) = 0.03 \sin \pi (2t - 0.01x)$,where $y$ and $x$ are in meters and $t$ is in seconds. The phase difference,at a given instant of time,between two particles $25 \ m$ apart in the medium is:

The equation of the wave is $Y = 10 \sin \left(\frac{2 \pi t}{30} + \alpha\right)$. If the displacement is $5 \text{ cm}$ at $t = 0$,then the total phase at $t = 7.5 \text{ s}$ will be (Given: $\sin 30^{\circ} = 0.5$)