A closed pipe is in resonance with a tuning fork at $27^{\circ} \mathrm{C}$ when its length is $20…
A closed pipe is in resonance with a tuning fork at $27^{\circ} \mathrm{C}$ when its length is $20 \mathrm{~cm}$. If the pipe is to be in resonance with the same tuning fork at $7{ }^{\circ} \mathrm{C}$ then the change in the length of the pipe required is nearly