When temperature increases,the frequency of a tuning fork

$A$ pair of tuning forks produces $2$ beats in a time interval of $0.4 \ s$. The beat frequency is .... $Hz$.

$A$ set of $28$ tuning forks is arranged in an increasing order of frequencies. Each fork produces '$x$' beats per second with the preceding fork and the last fork is an octave of the first. If the frequency of the $12^{\text{th}}$ fork is $152 \text{ Hz}$,the value of '$x$' (number of beats per second) is:

Two tuning forks have frequencies $380 \ Hz$ and $384 \ Hz$ respectively. When they are sounded together,they produce $4$ beats per second. After hearing the maximum sound,how long will it take to hear the minimum sound in seconds?

When two sound sources of the same amplitude but of slightly different frequencies $v_1$ and $v_2$ are sounded simultaneously,the sound one hears has a frequency equal to

$A$ tuning fork of frequency $n$ produces $x$ beats per second when sounded with a vibrating sonometer string. What must have been the frequency of the string, when a slight increase in tension produces lesser beats per second than before?