Question

A set of 24 tuning forks are so arranged in series that each gives 4 beats per second with the previous one and the last sounds the octave of the first. Then, the frequency of the fork is :

• A. 92 Hz
• B. 184 Hz
• C. 116 Hz
• D. 160 Hz

Answer 1

Answer: (A)

92 Hz

Since octave means twice the first,

hence, let the first frequency be $n$ then the successive frequencies will be $n+4,n+8...2n$

this forms an arithmetic progression

$L=A+(N-1)d$

$L$ is the last term

$A$ is the first

$N$ no of terms

$d$ is the difference

$2n=n+(24-1)4=92Hz$