$A$ sound is produced by plucking a string in a musical instrument,then

$A$ tuning fork of frequency $220 \,Hz$ produces sound waves of wavelength $1.5 \,m$ in air at $N.T.P$. The increase in wavelength when the temperature of air is $27^{\circ} C$ is nearly $\left(\sqrt{\frac{300}{273}}=1.05\right)$ (in $\,m$)

Sound waves of wavelength greater than that of audible sound are called

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 $1$).

$A$ $SONAR$ (sound navigation and ranging) uses ultrasonic waves to detect and locate objects under water. In a submarine equipped with a $SONAR$,the time delay between generation of a probe wave and the reception of its echo after reflection from an enemy submarine is found to be $77.0\; s$. What is the distance of the enemy submarine (in $; km$)? (Speed of sound in water $= 1450\; m/s$)

An engine approaches a hill with a constant speed. When it is at a distance of $0.9 \ km$,it blows a whistle,and the echo is heard by the driver after $5 \ s$. If the speed of sound in air is $330 \ m/s$,the speed of the engine is .... $m/s$.