A whistle revolves in a circle with an angular speed of $20\, rad/s$ using a string of length $50\, cm$. If the frequency of sound from the whistle is $385\, Hz$, then what is the minimum frequency heard by an observer, which is far away from the centre in the same plane  ..... $Hz$ (speed of sound is $340\, m/s$)

The equation of a stationary wave is

$y = 0.8\,\cos \,\,\left( {\frac{{\pi x}}{{20}}} \right)\,\sin \,200\,\pi t$

where $x$ is in $cm$ and $t$ is in $sec$ . The separtion between consecutive nodes will be .... $cm$

A set of $24$ tunning fork is arranged in a series of increasing frequencies. If each fork gives $4\, beats/second$ with the preceeding one and frequency of last tunning fork is two times of first fork. Find frequency of $5^{th}$ tunning fork  .... $Hz$

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 ..... $m$

A wave travelling along the $x-$ axis is described by the equation $y\ (x, t )\ =\ 0.005\ cos\ (\alpha x - \beta t )$ . If the wavelength and the time period of the wave in $0.08\ m$ and $2.0\ s$ respectively then $\alpha $ and $\beta $ in appropriate units are

Two waves represented by ${y_1} = a\sin \frac{{2\pi}}{\lambda }\left( {vt - x} \right)$ and ${y_2} = a\cos \frac{{2\pi }}{\lambda }\left( {vt - x} \right)$ are superposed. The resultant wave has an amplitude equal to