$A$ tuning fork produces four beats per second with two open organ pipes having lengths $30 \ cm$ and $31 \ cm$. Find the frequency of the tuning fork in $Hz$.

$A$ pipe $30 \, cm$ long is open at both ends. Which harmonic mode of the pipe resonates with a $1.1 \, kHz$ source? (Speed of sound in air $= 330 \, m/s$)

$A$ cylindrical tube open at both ends has a fundamental frequency $f$ in air. When the tube is dipped vertically in water so that one-third part of the tube is in water,the fundamental frequency of the air column becomes (neglect end correction).

Two open organ pipes of fundamental frequencies $n_1$ and $n_2$ are joined in series. The fundamental frequency of the new pipe so obtained will be

$A$ tuning fork of frequency $340 \ Hz$ is vibrated just above a tube of $120 \ cm$ height. Water is slowly poured in the tube. What is the minimum height of water necessary for resonance (in $cm$)?

$A$ uniform narrow $1.95 \, m$ long pipe is open at both ends. It resonates at two successive harmonics of frequency $275 \, Hz$ and $330 \, Hz$. The speed of sound in the tube is ...... $m/s$.