The fundamental frequency of a closed pipe is $400 \,Hz$. If $1/3$ of the pipe is filled with water,the frequency of the $2^{\text{nd}}$ harmonic of the pipe will be (Neglect end correction). (in $\,Hz$)

Two open organ pipes of fundamental frequencies $n_{1}$ and $n_{2}$ are joined in series. The fundamental frequency of the new pipe is

$A$ string of length $3 \ m$ and linear mass density $0.0025 \ kg/m$ is fixed at both ends. One of its resonance frequencies is $252 \ Hz$. The next higher resonance frequency is $336 \ Hz$. Then the fundamental frequency will be ..... $Hz$.

$A$ pipe $30 \ cm$ long is open at both ends. Which harmonic mode of the pipe is resonantly excited by a $1.1 \ kHz$ source? (Take speed of sound in air = $330 \ ms^{-1}$)

$A$ glass tube of $1 \,m$ length is filled with water. The water can be drained out slowly from the bottom of the tube. If a vibrating tuning fork of frequency $500 \,Hz$ is brought at the upper end of the tube, then the total number of resonances obtained are [Velocity of sound in air is $320 \,m/s$].

While measuring the speed of sound by performing a resonance column experiment,a student gets the first resonance condition at a column length of $18 \ cm$ during winter. Repeating the same experiment during summer,she measures the column length to be $x \ cm$ for the second resonance. Then