$A$ man is standing between two parallel cliffs and fires a gun. If he hears the first and second echoes after $1.5 \, s$ and $3.5 \, s$ respectively,the distance between the cliffs is .... $m$ (Velocity of sound in air $= 340 \, ms^{-1}$)

The figure represents the instantaneous picture of a longitudinal harmonic wave travelling along the negative $x$-axis. Identify the correct statement$(s)$ related to the movement of the points shown in the figure. The points of maximum rarefaction are

The figure below shows pressure variation in two different sound waves in air with time at a given position. Both the figures are drawn to the same scale. Which of the following statements is true?

When an aeroplane attains a speed higher than the velocity of sound in air,a loud bang is heard. This is because

An earthquake generates both transverse $S$ and longitudinal $P$ waves in the earth with speeds $4.5 \,km/s$ and $8.0 \,km/s$, respectively. $A$ seismograph records that the first $P$-wave arrives $3.5 \,min$ earlier than the first $S$-wave. From the seismograph, the epicentre of the earthquake is located at a distance of: (in $\,km$)

Sound waves travel fastest in