11. Natural radioactivity was discovered by

1. 1. Rutherfoed

   
   
   

   2. Becquerl

   
   
   

   3. Curic

   
   
   

   4. Schmidt

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NS

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12. In which process, a nucleus spontaneously breaks down by emitting radiation ?

1. 1. Radioactive decay

   
   
   

   2. Fusion

   
   
   

   3. Refraction

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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13. Emission of β-particle from an atom

1. 1. increases the number of protons in the atom

   
   
   

   2. increases the number of neutrons in the atom

   
   
   

   3. decreases the number of proton in the atom

   
   
   

   4. does not change the number of neutrons and protons in an atom

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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14. Which of the following is a radioactive element ?

1. 1. Sulphur

   
   
   

   2. Polonium

   
   
   

   3. Tellurium

   
   
   

   4. Selenium

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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15. Hydrogen bomb is based on the principle of
    

    	List-I (Characteristics)		List-II (Particles)
    F	Zero mass	1.	Positron
    G	Fractional charge	2.	Neutrind
    H	Fractional shin	3.	Quark
    J	Integral spin	4.	Photon

    Code

    	F	G	H	J
    A.	2	3	1	4
    B.	3	2	4	1
    C.	2	3	4	1
    D.	3	2	1	4

1. 1. A.

   
   
   

   2. B.

   
   
   

   3. C.

   
   
   

   4. D.

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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