N tuning forks are arranged in order of increasing frequency and any two successive tuning forks give n beats per second when sounded together. If the last fork gives double the frequency of the first (called as octave), Show that the frequency of the first tuning fork is `f=(N-1)n`.

Explanation

No. of tuning forks =N
The frequency of the first is double to be last tuning forks NHz
Let be frequency of the first tuning fork is f
Then be frequency of the last tuning fork is f(N-1)n
`f_("last") = f/2 rArr`
`an =a+(n-1)d`
(i.e.) `2f = f+(N-1)n`
=(N-1)n
f=(N-1)n