26. Two waves of the same frequency and intensity superimpose with each other in opposite phases. Then after superposition the

1. 1. Intensity increases to four times

   
   
   

   2. Intensity increases to two times

   
   
   

   3. Frequency increases to four times

   
   
   

   4. None of the above

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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27. 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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28. 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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29. 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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30. Penetrating power of X - rays can be increased by

1. 1. Increasing the potential difference

   
   
   

   2. Decreasing the potential difference between anode and cathode

   
   
   

   3. Decreasing the current of cathode filament

   
   
   

   4. Increasing the current of cathode filament

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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