Two tunning forks `A and B` when sounded together produce ` 3 beats//s`. What are the possible frequencies of `B`, if the frequency of `A is 400` cycle//s ? How can you verify which of the possible values is correct ?

Explanation

Frequency of `A`
`n_(A) = 400 s^(-1)`
Number of beats//s `= 3`.
`:. "Possible frequencies of" B`,
`n_(B) = 400 +- 3 = 403 or 397`
Verification of correct value . A small piece of wax is loaded on `B` , which decrease the frequency of `B`. Now the two forks `A and B` are again sounded , if the number of beats is less than `3` , the possible frequency of `B is 403`, but if number of beats is greater than `3` the possible frequency of `B is 397`.