Two waves of wavelengths $99\, cm$ and $100\, cm$ both travelling with velocity $396\, m/s$ are made to interfere. The number of beats produced by them per second is

$A$ tuning fork whose frequency as given by the manufacturer is $512 \ Hz$ is being tested with an accurate oscillator. It is found that the fork produces a beat of $2 \ Hz$ when the oscillator reads $514 \ Hz$,but produces a beat of $6 \ Hz$ when the oscillator reads $510 \ Hz$. The actual frequency of the fork is ..... $Hz$.

$A$ tuning fork gives $3$ beats with $50 \ cm$ length of sonometer wire. If the length of the wire is shortened by $1 \ cm$,the number of beats is still the same. The frequency of the fork is (in $Hz$)

Two tuning forks $A$ and $B$ are sounded together and produce $6$ beats per second. The frequency of tuning fork $B$ is $384 \,Hz$. When tuning fork $A$ is loaded with wax,the number of beats per second becomes $4$. What is the frequency of tuning fork $A$ in $Hz$?

The ratio of intensities between two coherent sound sources is $4:1$. The difference of loudness in $dB$ between maximum and minimum intensities when they interfere in space is:

When two waves of almost equal frequencies $v_1$ and $v_2$ reach a point simultaneously,the time interval between successive maxima is