Which of the following waves is used in sonography?

$A$ man fires a bullet standing between two cliffs. The first echo is heard after $3 \, s$ and the second echo is heard after $5 \, s$. If the velocity of sound is $330 \, m/s$,then the distance between the cliffs is .... $m$

$SONAR$ emits which of the following waves?

If the velocity of sound in a gas is $360\, m/s$ and the distance between a compression and the nearest rarefaction is $1\, m$,then the frequency of sound is ..... $Hz$.

Which of the following is not a transverse wave?

Sound travels in rocks in the form of