A stretched string is divided into three segments of lengths $50\,cm,\,\,40\,cm$ and $10\,cm$ with the help of bridges. Their vibrations will have frequencies in the ratio

Equation of a plane progressive wave is given by $y = 0.6\sin 2\pi \left( {t - \frac{x}{2}} \right)$. On reflection from a denser medium its amplitude becomes $2/3$ of the amplitude of the incident wave. The equation of the reflected wave is

A small source of sound moves on a circle as shown in the figure and an observer is standing on $O.$ Let $n_1,\, n_2$ and $n_3$ be the frequencies heard when the source is at $A, B$ and $C$ respectively. Then

A sound absorber attenuates the sound level by $20\,\, dB$. The intensity decrease by a factor of

Two identical flutes produce fundamental notes of frequency $300\,Hz$ at $27\,^oC$. If the temperature of air in one flute is increased to $31\,^oC$, the number of the beats heard per second will be

For a certain organ pipe three successive resonance frequencies are observed at $425\, Hz,$ $595\,Hz$ and $765\,Hz$ respectively. If the speed of sound in air is $340\,m/s,$ then the length of the pipe is ..... $m$