Question

You are given four tuning forks, the lowest frequency of the fork is $300Hz$. By striking two tuning forks at a time $1,2,3,5,7$ and $8$ beats are heard per second. The possible frequencies of other forks are

• A. $300Hz,302Hz,307Hz$
• B. $301Hz,303Hz,308Hz$
• C. $301Hz,304Hz,307Hz$
• D. $302Hz,304Hz,309Hz$

Answer 1

The correct option is B $301Hz,303Hz,308Hz$

To produce $1$ beat per second one of the frequency has to be $301Hz$

For maximum beats per second i.e. $8$ the possible frequency is $308Hz$

and in order to satisfy the other beats $2,3,5$ the only frequency between $300Hz$ and $308Hz$ which satisfies the other beats with $300Hz,301Hz,308Hz$ is $303Hz$