The fundamental frequency of an air column in a pipe open at both ends is $f_1$. Now $80\%$ of its length is immersed in water,the fundamental frequency of the air column becomes $f_2$. The ratio of $f_1:f_2$ is

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

Consider a gas with molar mass $M$. If sound at frequency $f$ is introduced to a tube of this gas at temperature $T$, an internal acoustic standing wave is set up with nodes separated by $L$. The adiabatic constant $\gamma = \frac{C_p}{C_v}$ is

$A$ metre-long tube open at one end,with a movable piston at the other end,shows resonance with a fixed frequency source (a tuning fork of frequency $340\; Hz$) when the tube length is $25.5\; cm$ or $79.3\; cm$. Estimate the speed of sound (in $m/s$) in air at the temperature of the experiment. The edge effects may be neglected.

$A$ flute,which we treat as a pipe open at both ends,is $34\, cm$ long. The fundamental frequency of the flute when all its holes are covered is .... $Hz$ [Take velocity of sound in air $= 340\, m/s$].

$A$ person blows into the open end of a long pipe. As a result,a high-pressure pulse of air travels down the pipe. When this pulse reaches the other end of the pipe,which of the following statements are true?
$(I)$ $A$ high-pressure pulse starts travelling up the pipe,if the other end of the pipe is open.
$(II)$ $A$ low-pressure pulse starts travelling up the pipe,if the other end of the pipe is open.
$(III)$ $A$ low-pressure pulse starts travelling up the pipe,if the other end of the pipe is closed.
$(IV)$ $A$ high-pressure pulse starts travelling up the pipe,if the other end of the pipe is closed.