86. The velocity of sound produced by a vibrating body varies

1. 1. Directly as the sq. root of density of the medium

   
   
   

   2. Inversely as the density of the medium

   
   
   

   3. Directly as the sq. root of frequency of the medium

   
   
   

   4. Inversely as the frequency of the medium

   
   
   

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   NA

   Correct Option: B

   NA

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87. Which one of the following types of glass can cut of ultraviolet rays ?

1. 1. Soda glass

   
   
   

   2. Pyrex glass

   
   
   

   3. Jena glass

   
   
   

   4. Crookes glass

   
   
   

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   NA

   Correct Option: D

   NA

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88. A particle is executing simple harmonic motion. Its total energy is proportional to its

1. 1. Displacement from equilibrium position

   
   
   

   2. Frequency of oscillation

   
   
   

   3. Square of amplitude of motion

   
   
   

   4. Velocity at equilibrium position

   
   
   

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   NA

   Correct Option: C

   NA

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89. If the density of oxygen is 16 times that of hydrogen, what will be the ratio of the velocities of sound in them ?

1. 1. 1 : 4

   
   
   

   2. 4 : 1

   
   
   

   3. 2 : 1

   
   
   

   4. 1 : 16

   
   
   

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   NA

   Correct Option: A

   NA

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90. Why is sound heard with more intensity through CO₂ than through the air ?

1. 1. Density of CO₂ is more than that of air

   
   
   

   2. Density of CO₂ is less than that of air

   
   
   

   3. Air is a bad conductor of heat

   
   
   

   4. CO₂ is a compound, but air is a mixture of gases

   
   
   

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   NA

   Correct Option: A

   NA

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