Oxygen is $16$ times heavier than hydrogen. Equal volumes of hydrogen and oxygen are mixed. The ratio of the speed of sound in the mixture to that in hydrogen is

The speed of sound in air:

Which of the following waves is used in sonography?

The velocities of sound at the same pressure in two monatomic gases of densities ${\rho _1}$ and ${\rho _2}$ are $v_1$ and $v_2$ respectively. If ${\rho _1}/{\rho _2} = 2$,then the value of $\frac{{{v_1}}}{{{v_2}}}$ is:

$A$ narrow sound pulse (for example,a short pip by a whistle) is sent across a medium.
$(a)$ Does the pulse have a definite $(i)$ frequency,$(ii)$ wavelength,$(iii)$ speed of propagation?
$(b)$ If the pulse rate is $1$ after every $20 \; s$,(that is,the whistle is blown for a split of a second after every $20 \; s$),is the frequency of the note produced by the whistle equal to $1/20$ or $0.05 \; Hz$?

The figure represents the instantaneous displacement-position graph of a longitudinal harmonic wave travelling along the negative $x$-axis. Identify the points of maximum compression.