Physics - Sound Wave Question with Solution | TestHub

PhysicsSound WaveStanding waveHard2 minPYQ_2020

PhysicsHardnumerical

A massless rod $BD$ of length $l$ is suspended by two identical massless strings $AB$ and $CD$ of equal lengths. A block of mass $m$ is suspended from a point $P$ such that $BP$ is equal to $x$ . If the fundamental frequency of the left wire is twice the fundamental frequency of the right wire, then the value of $\frac{l}{x}$ is

Answer:

5.00

Solution:

          $f \propto v \propto \sqrt{T}$

         $f_{AB} = 2 f_{CD}$

$∴$      $T_{AB} = 4 T_{CD}$    ...(i)

Further $Σ τ_{p} = 0$

$∴ T_{AB} (x) = T_{CD} (ℓ - x)$

or $4 x = l - x$    $(T_{AB} = 4 T_{CD})$

or $x = l / 5$

$\Rightarrow \frac{l}{x} = 5$

Stream:JEESubject:PhysicsTopic:Sound WaveSubtopic:Standing wave

⏱ 2mℹ️ Source: PYQ_2020

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