A train standing at the outer signal of a railway station blows a whistle of frequency $400\, Hz$ in still air. What is the frequency of the whistle for a platform observer when the train recedes from the platform with a speed of $10\, m/s$ ...... $Hz$ . (Speed of sound $= 340\, m/s$)
$388.57$
$412.12$
$340$
$100$
Three sound waves of equal amplitudes have frequencies $(f-1 ), f, (f+ 1)$. They superpose to give beats. The number of beats produced per second will be:
A cylindrical tube $(L = 120\, cm.)$ is resonant with a tuning fork of frequency $330\, Hz$. If it is filling by water then to get resonance again, minimum length of water column is ...... $cm$ $(v_{air} = 330\, m/s)$
A pulse on a string is shown in the figure. $P$ is particle of the string. Then state which of the following is incorrect
In the standing wave shown, particles at the positions $A$ and $B$ have a phase difference of
Figure shows a sinusoidal wave at a given instant Which points are in same phase ?