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Q.
The vibrations of four air columns under identical conditions are represented in the figure below. The ratio of frequencies $n_{p}: n_{q}: n_{r}: n_{s}$ will be
Waves
Solution:
$P, S$, will be $1^{\text {st }}$ and $2^{\text {nd }}$ harmonics of closed tube.
$P=\frac{v}{4 l}, S=\frac{v}{4 l}$
$Q, R$ are the $1^{\text {st }}$ and $2^{\text {nd }}$ harmonics of open pipe.
$Q=\frac{v}{2 l}, R=\frac{v}{l} $
$\therefore P: Q: R: S=1: 2: 4: 3$