121. Laplace's correction in the formula for the speed of sound given by Newton was needed because sound waves

1. 1. Are longitudinal

   
   
   

   2. Propagate isothermally

   
   
   

   3. Propagate adiabatically

   
   
   

   4. Have long wavelengths

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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122. The speed of sound in air at S.T.P. is 300 m / s. If the air pressure becomes double, the temperature remaining the same, the speed of sound would

1. 1. 1200 m / s

   
   
   

   2. 600 m / s

   
   
   

   3. 300 m / s

   
   
   

   4. 300 √2 m / s
      

   
   
   

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   NA

   Correct Option: C

   NA

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123. Ultrasonic waves are used for stirring liquid solutions because they

1. 1. Do not produce noise during the operation

   
   
   

   2. Are easy to produce

   
   
   

   3. Can produce perfectly homogeneous solution

   
   
   

   4. Do not produce chemical reactions in the solution

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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124. Assertion (A) : Radio waves bend in a magnetic field
     Reason (R) : Radio waves are electromagnetic in nature
     Codes :

1. 1. A and R are individually true and R is the correct explanation of A

   
   
   

   2. A and R are individually true, but R is not the correct explanation of A

   
   
   

   3. A is true, but R is false

   
   
   

   4. A is false, but R is true

   
   
   

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   NA

   Correct Option: D

   NA

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125. The velocity of sound in air is affected by change in the
     1. Atmospheric pressure
     2. Moisture content of air
     3. Temperature of air
     4. Composition of air
     Choose the correct answer

1. 1. 1 and 2

   
   
   

   2. 1, 3 and 4

   
   
   

   3. 1, 2 and 3

   
   
   

   4. 2, 3 and 4

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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