96. In which of the following sequences are the electromagnetic radiations in decreasing order of wave lengths

1. 1. Infrared, radio, X - rays, visible

   
   
   

   2. Radio, infrared, visible, X- rays

   
   
   

   3. Radio, visible, infrared, X -rays

   
   
   

   4. X- rays, visible, infrared, radio

   
   
   

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   NA

   Correct Option: A

   NA

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97. Which of the following electromagnetic waves has the longest wavelength ?

1. 1. Infrared rays

   
   
   

   2. Gamma rays

   
   
   

   3. Light rays

   
   
   

   4. Ultraviolet rays

   
   
   

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   NA

   Correct Option: B

   NA

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98. A string 1 m long is drawn by a vibrator attached to its end. The string vibrates in three segments. If the frequency of vibration of the vibrator is 480 Hz, then what is the speed of waves through the string ?

1. 1. 160 Hz

   
   
   

   2. 320 Hz

   
   
   

   3. 480 Hz

   
   
   

   4. 640 Hz

   
   
   

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   NA

   Correct Option: C

   NA

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99. How does the speed V of sound in air depend on atmospheric pressure P ?

1. 1. V ∝ P^-1

   
   
   

   2. V ∝ P²

   
   
   

   3. V ∝ P⁰

   
   
   

   4. V ∝ P^1/2

   
   
   

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   NA

   Correct Option: C

   NA

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100. What is the frequency of a wave whose time-period is 0.05 second ?

1. 1. 5 Hz

   
   
   

   2. 10 Hz

   
   
   

   3. 20 Hz

   
   
   

   4. 40 Hz

   
   
   

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   NA

   Correct Option: C

   NA

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