66. Neutrino is a particle which

1. 1. Has no charge but has spin

   
   
   

   2. Is charged like electron and has spin

   
   
   

   3. Has no charge and no spin

   
   
   

   4. None of the above

   
   
   

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   NA

   Correct Option: A

   NA

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67. To produce deflection in a television picture tube

1. 1. An electric field is used

   
   
   

   2. A magnetic fields is used

   
   
   

   3. Both electric and magnetic field are used

   
   
   

   4. None of the above

   
   
   

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   NA

   Correct Option: B

   NA

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68. In the photoelectric effect, electrons are emitted

1. 1. At a rate that is independent of the emitter

   
   
   

   2. At a rate that is proportional to the square of the amplitude of the incident radiation

   
   
   

   3. With a maximum velocity proportional to the frequency of incident radiation

   
   
   

   4. Only if the frequency of the incident radiation is above a threshold value

   
   
   

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   NA

   Correct Option: D

   NA

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69. In gamma (y) decay

1. 1. Both A and Z increase by 1

   
   
   

   2. Both A and Z decrease by 1

   
   
   

   3. Neither A nor Z changes

   
   
   

   4. A is always equal to Z

   
   
   

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   NA

   Correct Option: C

   NA

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70. The electron emitted in beta radiation originates from

1. 1. Inner orbits of atoms

   
   
   

   2. Free electrons existing in nucleus

   
   
   

   3. Decay of a neutron in a nucleus

   
   
   

   4. Photon escaping from the nucleus

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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