The distance between two consecutive points with phase difference of $45^{\circ}$ in a wave of frequency $300 \text{ Hz}$ is $4.0 \text{ m}$. The velocity of the travelling wave is (in $\text{km/s}$):

Which one of the following does not represent a travelling wave?

Given below are some functions of $x$ and $t$ to represent the displacement of an elastic wave.
$(i) \, y = 5 \cos (4x) \sin (20t)$
$(ii) \, y = 4 \sin (5x - t/2) + 3 \cos (5x - t/2)$
$(iii) \, y = 10 \cos (252\pi t) \cos (250\pi t)$
$(iv) \, y = 100 \cos (100\pi t + 0.5x)$
State which of these represent:
$(a)$ a travelling wave along $-x$ direction
$(b)$ a stationary wave
$(c)$ beats
$(d)$ a travelling wave along $+x$ direction.
Give reasons for your answers.

The displacement due to a wave moving in the positive $x$-direction is given by $y = \frac{1}{(1 + x^2)}$ at time $t = 0$ and by $y = \frac{1}{[1 + (x - 1)^2]}$ at $t = 2$ seconds,where $x$ and $y$ are in metres. The velocity of the wave in $m/s$ is

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 ..... $cm/sec$.

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