Length of an open organ pipe is twice the length of another closed organ pipe. The fundamental frequency of the open organ pipe is $100 \mathrm{Hz}$. The frequency of the third harmonic of the closed pipe is .

A student is performing an experiment using a resonance column and a tuning fork of frequency $244 {\mathrm{s}}^{-1}$. He told that the air in the tube has been replaced by another gas (assume that the column remains filled with the gas). If the minimum height at which resonance occurs is $\left(0.350\pm 0.005\right) \mathrm{m}$, the gas in the tube is (useful information: $\sqrt{167RT}=640 {\mathrm{J}}^{\frac{1}{2}} \mathrm{mole}{ }^{-\frac{1}{2}}, \sqrt{140RT}=590 {\mathrm{J}}^{\frac{1}{2}} \mathrm{mole}{ }^{-\frac{1}{2}}$. The molar mass $M$ in grams and given in the options. Take the values of $\sqrt{\frac{10}{M}}$ for each gas as given there). 

Two independent harmonics oscillators of equal mass are oscillating about the origin with angular frequencies $w_1$ and $w_2$ and have total energies $E_1$ and $E_2$ respectively. The variation of their momentum $p$ will positions $x$ are shown in figure 23.88. If $\frac{a}{b}=n^2 \mathrm{and} \frac{a}{R}=n$, then the correct equation(s) is (are)