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MHT CET202019 Oct 2020Morning ShiftPhysicsWaves and SoundActual

The fundamental frequency of a sonometer wire is 50 ~Hz for some length and tension. If the length is increased by 25 % by keeping tension same, then frequency change of second harmonic is

Options

  1. Adecreased by 10 %
  2. Bdecreased by 20 %
  3. Cdecreased by 5 %
  4. Ddecreased by 15 %

Correct answer

B. decreased by 20 %

Step-by-step solution

(D) aligned & n ₂ ₂= n ₁ ₁ & n ₂= ₁ ₂ n ₁= ₁ 1.25 R ₁ n ₁=0.8 n ₁ & n ₁- n ₂= n ₁(1-08)=0.2 n ₁ & n ₁- n ₂ n ₁ =0.2 aligned

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