106. 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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107. 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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108. Consider the following statement
     1. Microwaves are used in radar system for air craft navigation
     2. Microwave ovens are used for cooking purposes
     3. A radar using microwave can help in detecting the speed of tennis ball, cricket ball, automobile while in motion.
     Which of these statements are correct?

1. 1. 1 and 2

   
   
   

   2. 2 and 3

   
   
   

   3. 1 and 3

   
   
   

   4. 1, 2 and 3

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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109. When two sound waves are superimposed, beats are produced when they have

1. 1. Different amplitudes and phases

   
   
   

   2. Different velocities

   
   
   

   3. Different phases

   
   
   

   4. Different frequencies

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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110. If T is the reverberation time of an auditorium of volume V then

1. 1. T ∝ V

   
   
   

   2. T ∝ 1 / V

   
   
   

   3. T ∝ V²

   
   
   

   4. T ∝ 1 / V²

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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