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 …. $\%$

The length of a son meter wire $AB$ is $110\; cm$. Where should the two bridges be placed from $A$ to divide the wire in $3$ segments whose fundamental frequencies are in the ratio of $1:2:3$?

A sine wave of wavelength $\lambda $ is travelling in a medium. The minimum distance between the two particles, always having same speed, is

A sonometer wire, with a suspended mass of $M = 1\, kg$, is in resonance with a given tuning fork. The apparatus is taken to the moon where the acceleration due to gravity is $(1/6)$ that on earth. To obtain resonance on the moon, the value of $M$ should be ……… $kg$

The rope shown at an instant is carrying a wave travelling towards right, created by a source vibrating at a frequency $n$. Consider the following statements

$I.$ The speed of the wave is $4n \times ab$

$II.$ The medium at $a$ will be in the same phase as $d$ after $\frac{4}{{3n}}s$

$III.$ The phase difference between $b$ and $e$ is $\frac{{3\pi }}{2}$

Which of these statements are correct