A sonometer wire under a tension of `10 kg` weight is in unsion with a tuning fork of frequency `320 H_(Z)` . To make the wire vibrate in unsion with a tuning fork of frequency `256 h_(Z)` , the tension should be altered by

Options

A. `3.6 kg` decreased
B. `3.6 kg` increased
C. `6.4 kg` decreased
D. `6.4 kg` increased

Answer

A

Explanation

`f prop nu prop sqrt(T)`
`(T rarr` tension)
:. `f_(1) / (f_(2)) = sqrt(T_(1)/(T_(2)))rArr T_(2) = T_(1) (f_(2)/(f_1))^(2)`
= `(10) ((256) / (320))^(2) = 6.4 kg`