If you set up the ninth harmonic on a string fixed at both ends, its frequency compared to the seventh harmonic

Standing waves are produced in $10 \,m$ long stretched string fixed at both ends. If the string vibrates in $5$ segments and wave velocity is $20 \,m / s$, the frequency is ……. $Hz$

A string of length $1\, m$ and mass $5\, g$ is fixed at both ends. The tension in the string is $8.0\, N$. The string is set into vibration using an external vibrator of frequency $100\, Hz$. The separation between successive nodes on the string is close to …. $cm$

The transverse displacement of a string clamped at its both ends is given by 

$y\left( {x,t} \right) = 2\,\sin \,\left( {\frac{{2\pi }}{3}x} \right)\,\cos \,\left( {100\,\pi t} \right)$ 

where $x$ and $y$ are in $cm$ and $t$ is in $s$. Which of the following statements is correct ?

A steel rod $100 cm$ long is clamped at its mid-point. The funda-mental frequency of longitudinal vibrations of the rod is given to be $2.53 kHz$. What is the speed of sound in steel …. $km/s$