Atoms and Nuclei (NEET Physics): Questions 51  56 of 67
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Question number: 51
» Atoms and Nuclei » Radioactive Decay Law
Question
The halflife of radioactive Radon is 3.8 days. The time at the end of which of the Radon sample will remain undecayedis
(Given log _{10} e = 0.4343)
Choices
Choice (4)  Response  

a.  33 days 

b.  3.8 days 

c.  76 days 

d.  16.5 days 

Question number: 52
» Atoms and Nuclei » MassEnergy Relation
Question
Energy of each photon obtained in the pair production process will be, if the mass of electron or positron is a. m. u
Choices
Choice (4)  Response  

a.  0.213 MeV 

b.  0.465 MeV 

c.  0.123 MeV 

d.  0.321 MeV 

Question number: 53
» Atoms and Nuclei » Radioactive Decay Law
Question
Halflife of Bi ^{210} is 5 days. If we start with 50, 000 atoms of this isotope, the number of atoms left over after 10 days is
Choices
Choice (4)  Response  

a.  5, 000 

b.  25, 000 

c.  20, 000 

d.  12, 500 

Question number: 54
» Atoms and Nuclei » MassEnergy Relation
Question
Sun radiate energy in all direction. The average energy received at earth is 1.4 KW/m ^{2}. The average distance between the earth and the sun is 1.5 ⨯ 10 ^{n} m. If this energy is released by conservation of mass into energy, then the mass lost per day by the sun is approximately (Use l day = 86400 sec)
Choices
Choice (4)  Response  

a.  3.8 ⨯ 10 ^{14} kg. 

b.  7.6 ⨯ 10 ^{14} kg 

c.  3.8 ⨯ 10 ^{12} kg 

d.  4.4 ⨯ 10 ^{9} kg 

Question number: 55
» Atoms and Nuclei » Radioactivity
Question
If _{92} U ^{238} undergoes successively 8 α decays and 6 β decays, then resulting nucleus is,
Choices
Choice (4)  Response  

a.  _{82} U ^{206} 

b.  _{82} U ^{214} 

c.  _{82} U ^{210} 

d.  _{82} Pb ^{206} 

Question number: 56
» Atoms and Nuclei » Radioactivity
Assertion (Ꭺ)
The mass of β particles when they are emitted is higher than the mass of electrons obtained by other means.
Reason (Ꭱ)
β particle and electron, both are similar particles.
Choices
Choice (4)  Response  

a.  Ꭺ is true but Ꭱ is false 

b.  Both Ꭺ and Ꭱ are true but Ꭱ is NOT the correct explanation of Ꭺ 

c.  Both Ꭺ and Ꭱ are true and Ꭱ is the correct explanation of Ꭺ 

d.  Both Ꭺ and Ꭱ are false 
