The fundamental frequency of open tubev0​=2l0​v​…(i)That of closed pipevc​=4lc​v​…(ii)According to the problem lc​=2l0​​Thus vc​=2l0​​v​⇒vc​2lv​… (iii)From equations (i) and (iii)v0​=vc​Thus, vc​=f(. as v0​=f is given )