Question

The two parts of a sonometer wire divided by a movable knife edge , differ in length by `2 mm` and produce `1 beat//s` , when sounded together . Find their frequencies if the whole length of wire is `1.00 m`.

Answer 1

Correct Answer - `249.5 Hz , 250.5 Hz`
`l_(1) + l_(2) = 100 cm , l_(1) - l_(2) = 0.2 cm`
`:. l_(1) = 50.1 cm and l_(2) = 49.9 cm`
Also `nl = constant `
` n xx 50.1 = ( n + 1) xx 49.9 `
`n = 249.5 Hz`
`:. n_(1) = 249.5 Hz and n_(2) = n + 1 = 250.5 Hz`