If the temperature of the atmosphere is increased,which of the following characteristics of a sound wave is affected?

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.

$A$ string is stretched so that its length is increased by $\frac{1}{\eta }$ of its original length. The ratio of the fundamental frequency of transverse vibration to that of the fundamental frequency of longitudinal vibration will be

Why are the bells in temples and schools made of metal and not of wood?

$A$ plane wave of sound traveling in air is incident upon a plane surface of a liquid. The angle of incidence is $60^{\circ}$. The speed of sound in air is $300 \ m/s$ and in the liquid it is $600 \ m/s$. Assume Snell's law to be valid for sound waves.

$A$ 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: