A metal wire of linear mass density of $9.8\, g/m$ is stretched with a tension of $10 kg$ weight between two rigid supports $1$ metre apart. The wire passes at its middle point between the poles of a permanent magnet, and it vibrates in resonance when carrying an alternating current of frequency $n.$ The frequency $n$ of the alternating source is ..... $Hz$

The tension of a stretched string is increased by $69\%$. In order to keep its frequency of vibration constant, its length must be increased by .... $\%$

A string is stretched between two fixed points separated by $75\,cm$ . It is observed to have resonant frequencies of $420\,Hz$ and $315\,Hz$ . There are no other resonant frequencies between these two. Then, the lowest resonant frequency for this string is  ..... $Hz$

A $43\, m$ long rope of mass $5.0\, kg$ joins two rock climbers. One climber strikes the  rope and the second one feels the effect $1.4\, s$ later. What is the tension in the rope .... $N$ ?

Explain the reflection of wave at rigid support.

Stationary waves are produced in $10\,m$  long stretched string. If the string Vibrates in $5$ segments and wave velocity  $20\,m/s$ the frequency is ..... $Hz$