When a wave travelling in a medium is reflected from the boundary of a denser medium,which of the following will not change?

The equation of a progressive wave is $y = a \sin(200t - x)$,where $x$ is in meters and $t$ is in seconds. The velocity of the wave is ..... $m/s$.

$A$ 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 .........

The equation of a plane progressive wave is given by $y = 0.025 \sin (100t + 0.25x)$. The frequency of this wave would be

$A$ simple harmonic progressive wave is given by $Y = Y_0 \sin 2 \pi (nt - \frac{x}{\lambda})$. If the wave velocity is $(1/8)^{\text{th}}$ of the maximum particle velocity,then the wavelength is

The wave described by $y = 0.25 \sin(10\pi x - 2\pi t)$,where $x$ and $y$ are in meters and $t$ is in seconds,is a wave travelling along the