36. 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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   NA

   Correct Option: A

   NA

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37. 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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   NA

   Correct Option: D

   NA

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38. When X -rays are produced, then

1. 1. Heat is produced on the target

   
   
   

   2. Heat is observed by the target

   
   
   

   3. Temperature of the target is being constant

   
   
   

   4. A luminous light is to be seen on the target

   
   
   

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   NA

   Correct Option: C

   NA

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39. Penetrating power of X-rays does not depend on

1. 1. Wavelength

   
   
   

   2. Energy

   
   
   

   3. Potential difference

   
   
   

   4. Current in the filament

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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40. Consider the following statements
    1. Light of longer wavelength is scattered much more than the light of shorter wavelength.
    2. The speed of visible light in water is 0.95 times the speed in vacuum.
    3. Radio waves are produced by rapidly oscillating electrical currents.
    4. To detect the overspending vehicles, police use the Doppler effect of reflected short radio waves
    Which of these statements are correct?

1. 1. 1 and 2

   
   
   

   2. 1 and 3

   
   
   

   3. 2 and 4

   
   
   

   4. 3 and 4

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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