36. In a discharge tube, ionization of enclosed gas is produced due to collisions between

1. 1. Neutral gas atoms / molecules

   
   
   

   2. Positive ions and neutral atoms / molecules

   
   
   

   3. Negative electrons and neutral atoms / molecules

   
   
   

   4. Photons and neutral atoms / molecules

   
   
   

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   NA

   Correct Option: C

   NA

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37. The phenomenon of ejection of electrons from the surface of metals, when light of suitable wavelength falls on it, is known as

1. 1. Electrolysis

   
   
   

   2. Ionization

   
   
   

   3. Photo electric effect

   
   
   

   4. None of these

   
   
   

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   NA

   Correct Option: C

   NA

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38. Which of the following phenomena is observed when black discharge occurs in a discharge tube ?

1. 1. The wall of the tube opposite to the cathode glow

   
   
   

   2. Striations are seen

   
   
   

   3. A glow appears at the cathode

   
   
   

   4. Positive column appears

   
   
   

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   NA

   Correct Option: A

   NA

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39. Energy is continuously generated in the sun due to

1. 1. Nuclear fusion

   
   
   

   2. Nuclear fission

   
   
   

   3. Radioactivity

   
   
   

   4. Artificial radioactivity

   
   
   

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   NA

   Correct Option: A

   NA

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40. Nuclear fusion is the source of energy in

1. 1. Sun and atom bomb

   
   
   

   2. Nuclear reactor and sun

   
   
   

   3. Sun and hydrogen bomb

   
   
   

   4. Nuclear reactor and atom bomb

   
   
   

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   NA

   Correct Option: D

   NA

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