$A$ hospital uses an ultrasonic scanner to locate tumours in a tissue. The operating frequency of the scanner is $4.2 \, MHz$. The speed of sound in a tissue is $1.7 \, km/s$. The wavelength of sound in the tissue is close to:

Earthquakes generate sound waves inside the earth. Unlike a gas,the earth can experience both transverse $(S)$ and longitudinal $(P)$ sound waves. Typically,the speed of $S$ wave is about $4.0 \; km/s$,and that of $P$ wave is $8.0 \; km/s$. $A$ seismograph records $P$ and $S$ waves from an earthquake. The first $P$ wave arrives $4 \; min$ before the first $S$ wave. Assuming the waves travel in a straight line,at what distance (in $km$) does the earthquake occur?

The following phenomenon cannot be observed for sound waves:

Use the formula $v=\sqrt{\frac{\gamma P}{\rho}}$ to explain why the speed of sound in air:
$(a)$ is independent of pressure,
$(b)$ increases with temperature,
$(c)$ increases with humidity.

Assume that the displacement $(s)$ of air is proportional to the pressure difference $(\Delta p)$ created by a sound wave. Displacement $(s)$ further depends on the speed of sound $(v)$,density of air $(\rho)$,and the frequency $(f)$. If $\Delta p \approx 10 \, Pa$,$v \approx 300 \, m/s$,$\rho \approx 1 \, kg/m^3$,and $f \approx 1000 \, Hz$,then $s$ will be of the order of (take multiplicative constant to be $1$).

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?