When a tuning fork vibrates,the waves produced in the fork are

The particle displacement of a travelling longitudinal wave is represented by $\xi = \xi(x, t)$. The midpoints of a compression zone and an adjacent rarefaction zone are represented by the letters $C$ and $R$. Which of the following is true?

The velocity of sound is $v_s$ in air. If the density of air is increased to $4$ times,then the new velocity of sound will be

Which of the following frequencies of sound waves is audible to human beings?

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

The path difference between two particles of a sound wave is $50 \ cm$ and the phase difference between them is $1.8 \pi$. If the speed of sound in air is $340 \ ms^{-1}$, the frequency of the sound wave is (in $Hz$)