What is the velocity of a wave in a monoatomic gas having a pressure of $1 \, kPa$ and a density of $2.6 \, kg/m^3$?

$A$ 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:

$A$ steel rod $100 \; cm$ long is clamped at its middle. The fundamental frequency of longitudinal vibrations of the rod is given to be $2.53 \; kHz$. What is the speed (in $km/s$) of sound in steel?

$Assertion :$ The change in air pressure affects the speed of sound.
$Reason :$ The speed of sound in gases is proportional to the square of pressure.

Velocity of sound in air:
$I.$ Increases with temperature
$II.$ Decreases with temperature
$III.$ Increases with pressure
$IV.$ Is independent of pressure
$V.$ Is independent of temperature
Choose the correct answer.

What will be the shape of the graph of the speed of sound in air versus pressure at a constant temperature?