Question

A set of 64 tuning forks is arranged decreasing order any one of them gives 4 BPS with preceding one if the frequency of first fork is octave of last calculate frequency of 1st and 30th fork

Answer 1

Answer:

84 Hz

*Explanation*

84 Hz

Let the frequency of the last fork be n.

Therefore, the frequency of the 1st fork is 2n and any two successive forks produce 3 beat/s

The frequency of the 2nd fork will be

2n−3.

Frequency of the 3rd fork will be, 2n−6

Now, the frequency of the 25th fork will be,

2n−(25−1)×3=n

2n−72=n

n=72Hz

The frequency of 1st fork will, 2n=2×72=144Hz

The frequency of 21st fork is,

f=2n−(21−1)×3

f=144−20×3

f=144−60=84Hz

The correct option is D.