Two tuning forks having frequency $256\, Hz \,(A)$ and $262\, Hz \,(B)$ tuning fork. $A$ produces some beats per second with unknown tuning fork, same unknown tuning fork  produce double beats per second from $B$ tuning fork then the frequency of unknown tuning fork is :- ............ $\mathrm{Hz}$

A closed organ pipe has a frequency $'n'$. If its length is doubled and radius is halved, its frequency nearly becomes

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

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 :-

$y = a\,cos\,(kx -\omega t)$ superposes on another wave giving a stationary wave having node at $x = 0$ . What is the equation of the other wave 

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  .... $Hz$