Question

Two tuning fork when sounded together, produce 3 `beats//s`. One of the fork is in unison with `27 cm` length of sonometer wire and other with `28 cm` length of the same wire. The frequencies of the two tuning forks are
A. 87:84 Hz
B. 42:39 Hz
C. 81:78 Hz
D. 84:81 Hz

Answer 1

Correct Answer - D
`(v_1)/(v_2)=(28)/(27)`
`v_1-v_2=3or(28)/(27)v_2-v_2=3`
`v_2=27x3Hz=81Hz`
or `v_1=v_2=3=(81+3)Hz`
or `v_1=84Hz`