A massless rod is suspended by two identical strings AB and CD of equal length. A block of mass $m$ is suspended from point $O$ such that BO is equal to $x$. Further, it is observed that the frequency of 1st harmonic (fundamental frequency) in AB is equal to 2 nd harmonic frequency in CD. Then, length of BO is

Two waves $y_1=\mathrm{A} \cos (0.5 \pi x-100 \pi t)$ and $y_2=\mathrm{A} \cos (0.467 \pi x-92 \pi t)$ are travelling in a pipe placed along $x$-axis.

Find the number of times the intensity is maximum in the time interval of 1 sec.

Two waves $y_1=\mathrm{A} \cos (0.5 \pi x-100 \pi t)$ and $y_2=\mathrm{A} \cos (0.467 \pi x-92 \pi t)$ are travelling in a pipe placed along $x$-axis.

Find the wave velocity of louder sound.

Two waves $y_1=\mathrm{A} \cos (0.5 \pi x-100 \pi t)$ and $y_2=\mathrm{A} \cos (0.467 \pi x-92 \pi t)$ are travelling in a pipe placed along $x$-axis.

Find the number of times $y_1+y_2=0$ at $x=0$ in $1 s$.