The fundamental frequency of a sonometer with a weight of $4\,kg$ is $256\,Hz$ . The weight required to produce its octave is .... $kg-wt$

A wire of length $30\,cm$, stretched between rigid supports, has it's $n^{\text {th}}$ and $(n+1)^{\text {th}}$ harmonics at $400\,Hz$ and $450\; Hz$, respectively. If tension in the string is $2700\,N$, it's linear mass density is.........$kg/m$.

A man can hear sounds in frequency range $120\,Hz$ to $12020\,Hz$. only. He is vibrating a piano string having a tension of $240\,N$ and mass of $3\,gm$ . The string has a length of $8\,m$ . How many different frequencies can he hear ?

A rod of length $1.2\,m$ is clamped at the mid point and its fundamental frequency is $2\,MHz$ , then speed of wave inside the rod?

Explain the reflection of wave at rigid support.

Two open organ pipes of fundamental frequencies $n_{1}$ and $n_{2}$ are joined in series. The fundamental frequecny of the new pipe so obtained will be