What causes the formation of beats in sounds?

Beats are produced by frequencies $v_1$ and $v_2$ $(v_1 > v_2)$. The duration of time between two successive minima is

The beats are produced by two sound sources of same amplitude and of nearly equal frequencies. The maximum intensity of beats will be ...... that of one source.

Two tuning forks $A$ and $B$ produce notes of frequencies $258 \,Hz$ and $262 \,Hz$. An unknown note sounded with $A$ produces certain beats. When the same note is sounded with $B$, the beat frequency gets doubled. The unknown frequency is (in $\,Hz$)

Beats are produced by waves $y_1 = a \sin(2000 \pi t)$ and $y_2 = a \sin(2008 \pi t)$. The number of beats heard per second is

$A$ and $B$ are two wires whose fundamental frequencies are $256 \text{ Hz}$ and $382 \text{ Hz}$ respectively. When the third harmonic of $A$ and the second harmonic of $B$ are sounded together, the number of beats heard in two seconds will be: