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NTA Abhyas JEE Main2020PhysicsWaves and SoundPractice

A sound absorber attenuates the sound level by 20 dB. The intensity decreases by a factor of

Options

  1. A100
  2. B1000
  3. C10000
  4. D10

Correct answer

A. 100

Step-by-step solution

L 1 = 10 log I 1 I 0 ; L 2 = 10 log I 2 I 0 ∴ L 1 - L 2 = 10 log I 1 I 0 - 10 log I 2 I 0 or Δ L = 10 log I 1 I 2 or 20 dB = 10 log I 1 I 2 or 10 2 = I 1 I 2 or I 2 = I 1 100 .

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