A string when stretched with a weight of 9 kg weigth produces a note of frequency 256. Calculate the weight to produces an octave of the note.

Options

A. 36 kg wt
B. 9/4 kg wt
C. 18 kg wt
D. 4 kg wt.

Answer

A

Explanation

For stretched string v = `(1)/(2l ) sqrt((T)/(m)) rArr v prop sqrt(T)` .
one octane higher means to double the frequency.
`therefore (v_(2))/(v_(1)) = sqrt((T_(2))/(T_(1))) " " rArr " " (2 xx 256)/(256) = sqrt((T)/(9 "kg wt"))`
`therefore T_(2) = 36 ` kg wt.
Hence correct choice is (a).