When a wave enters into a rarer medium from a denser medium,the property of the wave which remains constant is

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

The maximum particle velocity in a wave motion is half the wave velocity. Then the amplitude of the wave is equal to

The displacement $y$ of a particle in a medium can be expressed as: $y = 10^{-6} \sin(100t + 20x + \pi/4) \ m$,where $t$ is in seconds and $x$ is in meters. The speed of the wave is ... $m/s$.

The equation of a wave is given by $y = 10 \sin \left(\frac{2 \pi t}{30} + \alpha\right)$. If the displacement is $5 \ cm$ at $t = 0 \ s$,then the total phase angle at $t = 7.5 \ s$ will be:

If the speed of the wave shown in the figure is $330 \ m/s$ in the given medium,then the equation of the wave propagating in the positive $x$-direction will be (all quantities are in $M.K.S.$ units).