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For air at room temperature, the atmospheric pressure is 1.0 10⁵ Nm ⁻² and density of ait is 1.2 kgm ⁻³ . For a tube of length 1.0 m , closed at one end, the lowest frequency array lllllll generated is & 84 & Hz. & The & value & of array (ratio of two specific heats) for air is

Options

  1. A2.1
  2. B1.5
  3. C1.8
  4. D1.4

Correct answer

D. 1.4

Step-by-step solution

The tube is closed at one end. So, it will act like a closed organ pipe. The lowest frequency produced in the tube array l l= 4 , =4 l=1 m f=84 Hz V=n =84 4 array When wave propagate in air, the velocity Here, array l v= p p=1.0 10⁵ N / m ² array aligned &=1.2 kg / m ³ V² &= P &= v ² P &= (84 4)² 1.2 1.0 10⁵ &= 135472.2 10⁵ =1.354 &=1.4 aligned

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