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

In the standing wave shown, particles at the positions $A$ and $B$ have a phase difference of

A transverse wave is passing through a stretched string with a speed of $20\  m/s$ . The tension in the string is $20\ N$ . At a certain point $P$ on the string, it is observed that energy is being transferred at a rate of $40\ mW$ at a given instant. Find the speed of point $P$

The transverse displacement of a string (clamped at its both ends) is given by $y(x,t) = 0.06$ $sin\, (2\pi x /3)\, cos\, (120\, \pi t)$. All the points on the string between two consecutive nodes vibrate with

A racing car moving towards a cliff sounds its horn. The driver observes that the sound reflected from the cliff has a pitch one octave higher than the actual sound of the horn. If $v$ is the velocity of sound, the velocity of the car will be

Beats are produced by two waves $y_1 = a\, sin\, (1000\, \pi t)$ and $y^2 = a\, sin\, (998\, \pi t)$ The number of beats heard per second is