A wire of length L , diameter ' d ' density of material ' e ' is under tension ' T ', having fundamental frequency of vibration $\mathrm{n}_{\mathrm{A}}$. Another wire of length 2 L , tension 2 T , density 2 e and diameter 3 d has fundamental frequency of vibration $\mathrm{n}_{\mathrm{B}}$. The ratio $\mathrm{n}_{\mathrm{B}}: \mathrm{n}_{\mathrm{A}}$ is

The frequency of a tuning fork is 256 Hz . It will not resonate with the tuning fork of frequency

In an organ pipe closed at one end; the sum of the frequencies of first three overtones is 3930 Hz . The frequency of the fundamental mode of organ pipe is

A progressive wave of frequency 400 Hz is travelling with velocity $336 \mathrm{~m} / \mathrm{s}$. How far apart are the two points on a wave which are $60^{\circ}$ out of phase?