If the end correction of an open pipe is $0.8 \ cm$,then the inner radius of that pipe will be

$A$ gas is filled in an organ pipe and it is sounded in its fundamental mode. Choose the correct statement$(s)$ : ($T$ = constant)

$A$ source of frequency $340 \,Hz$ is kept above a vertical cylindrical tube closed at the lower end. The length of the tube is $120 \,cm$. Water is slowly poured in just enough to produce resonance. Then, the minimum height (velocity of sound $= 340 \,m/s$) of the water level in the tube for that resonance is (in $\,m$)

$A$ tuning fork of frequency $340 \, Hz$ is sounded above an organ pipe of length $120 \, cm$. Water is now slowly poured in it. The minimum height of water column required for resonance is .... $cm$ (speed of sound in air $= 340 \, m/s$)

$A$ 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 of sound in steel in $km/s$?

What is a harmonic of oscillation (mode)? Give an explanation of different harmonics (modes).