Điều kiện: l = $\left(2k+1\right)\dfrac{\lambda }{4}\Rightarrow \lambda =\dfrac{4l}{2k+1}$
$\Rightarrow$ $f=\dfrac{v}{\lambda }=\left(2k+1\right)\dfrac{\lambda }{4l}=\left(2k+1\right)f_{0}$
Ta có: $f_{0}=112Hz\Rightarrow \dfrac{v}{4l}=112\Rightarrow l=0,75\left(m\right)$
Âm cơ bản $\Leftrightarrow$ k=0
$\Rightarrow$ $\lambda _{max}\Leftrightarrow \left(2k+1\right)_{min}=3\left(k=1\right)$
$\Rightarrow$ $\lambda _{max}=1\left(m\right)$