Figure shows a sinusoidal wave at a given instant Which points are in same phase ?

A sound-source is moving in a circle and an observer is outside the circle at $O$ as shown in figure. If the frequencies as heard by the listener are $\nu _1, \nu _2$ and $\nu _3$ when the source is at $A, B$ and $C$ position, respectively, then

Dependence of disturbances due to two waves on time is shown in the figure. The ratio of their intensities $I_1 / I_2$ will be

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

A train is moving towards a stationary observer. Which of the following curve best represents the frequency received by observer $f$ as a function of time ?

A string of mass $100\, gm$ is clamped between two rigid support. A wave of amptitude $2\, mm$ is generated in string. If angular frequency of wave is $5000\, rad/s$ then total energy of the wave in string is ..... $J$