Two points on a travelling wave having frequency $500\, Hz$ and velocity $300\, m/s$  are $60^o$ out of phase, then the minimum distance between the two points is ..... $m$

Two wires are producing fundamental notes of the same frequency. Change in which of the following factors of one wire will not produce beats between them

Two identical strings $X$ and $Z$ made of same material have tension $T _{ x }$ and $T _{ z }$ in them. If their fundamental frequencies are $450\, Hz$ and $300\, Hz ,$ respectively, then the ratio $T _{ x } / T _{ z }$ is$.....$

A string is stretched between fixed points separated by $75.0\,\, cm.$ It is observed to have resonant frequencies of $420\,\, Hz$ and $315\,\, Hz$. There are no other resonant frequencies between these two. The lowest resonant frequency for this string is .... $Hz$

A metallic wire of length $L$ is fixed between two rigid supports. If the wire is cooled through a temperature difference $\Delta T$ ($Y$ = young’s modulus, $\rho$ = density, $\alpha$ = coefficient of linear expansion) then the frequency of transverse vibration is proportional to : 

The fundamental frequency of a sonometer wire of length $l$ is $n_0$ . A bridge is now introduced at a distance of $\Delta l ( < < l)$ from the centre of the wire. The lengths of wire on the two sides of the bridge are now vibrated in their fundamental modes. Then, the beat frequency nearly is