101. Consider the following statements with reference to X - rays
     1. They produce heat when absorbed by matter
     2. They are generated when fast moving electrons
     3. They can penetrate through a thin sheet of aluminium.
     Which of the statements given above are correct ?

1. 1. 1, 2 and 3

   
   
   

   2. 1 and 2

   
   
   

   3. 2 and 3

   
   
   

   4. 1 and 3

   
   
   

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   NA

   Correct Option: A

   NA

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102. Velocity of sound in air
     1. Increases with temperature
     2. Decreases with temperature
     3. Increases with pressure
     4. Is independent of pressure
     5. Is independent of temperature

1. 1. only 1 and 2 are true

   
   
   

   2. only 2 and 4 are true

   
   
   

   3. only 1 and 3 are true

   
   
   

   4. only 1 and 4 are true

   
   
   

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   NA

   Correct Option: D

   NA

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103. With the increase in temperature, the frequency of the sound from an organ pipe

1. 1. Decreases

   
   
   

   2. Increases

   
   
   

   3. Remain unchanged

   
   
   

   4. Changes erractically

   
   
   

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   NA

   Correct Option: B

   NA

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104. Stationary waves of frequency 300 Hz are formed in a medium in which the velocity of sound is 1200 m/s. The distance between a node and the neighbouring anti node is

1. 1. 1 m

   
   
   

   2. 2 m

   
   
   

   3. 3 m

   
   
   

   4. 4 m

   
   
   

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   NA

   Correct Option: A

   NA

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105. If the ratio of the amplitudes of two waves is 4 : 3, then the ratio of maximum and minimum intensity is

1. 1. 16 : 9

   
   
   

   2. 1 : 16

   
   
   

   3. 1 : 49

   
   
   

   4. 49 : 1

   
   
   

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   NA

   Correct Option: D

   NA

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