Two tuning fork A and B give 5 beats `//` sec. A resounds with a closed column of air 15 cm long and B with an open column of air 30.5 cm long. Calculate their frequecies. Neglect end correction.

Explanation

Freq. of A, `n_(1)=(upsilon)/(4l_(1))=(upsilon)/(4xx0.15)=(upsilon)/(0.6)`
Freq. of B, `n_(2)=(upsilon)/(2l_(2))=(upsilon)/(2xx0.305)=(upsilon)/(0.61)`
Beat frequency, `m=n_(1)-n_(2)`
`5=(upsilon)/(0.6)-(upsilon)/(0.61)=((0.61-0.6)upsilon)/(0.6xx0.61)`
`upsilon=(5xx0.6xx0.61)/(0.01)=183m//s`
`:. n_(1)=(upsilon)/(0.6)=(183)/(0.6)=305Hz`
`n_(2)=(upsilon)/(0.61)=(183)/(0.61)=300Hz`