What is the phase change of a wave when it reflects from a rigid support?

What is the phase difference between two successive crests in a wave?

You have learnt that a travelling wave in one dimension is represented by a function $y=f(x, t)$ where $x$ and $t$ must appear in the combination $x-vt$ or $x+vt$,i.e.,$y=f(x \pm vt)$. Is the converse true? Examine if the following functions for $y$ can possibly represent a travelling wave:
$(a)$ $(x-vt)^2$
$(b)$ $\log[(x+vt)/x_0]$
$(c)$ $1/(x+vt)$

$A$ boat at anchor is rocked by waves whose crests are $100 \,m$ apart and velocity is $25 \,m/s$. The boat bounces up once in every (in $\,s$)

$A$ transverse wave is represented by $y = A \sin(\omega t - kx)$. For what value of the wavelength is the wave velocity equal to the maximum particle velocity?

Which of the following is different from others?