N1 atoms of a radioactive element emit N2 beta particles per seco

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

231.

If  the  half  lives  of  a  radioactive  element  for  α  and  β  decay  are  4  years  and  12  years  respectively,  the  ratio  of  its  initial  activity  and  that  after  12  years will be

  • 6.25 %

  • 12.5 %

  • 25 %

  • 50 %


232.

A radioactive nucleus is being produced  at  a constant  rate  α  per  second. Its  decay  constant  is  λ. If N0 are the  number  of  nuclei  at  time  t = 0, then the maximum number of  nuclei possible are

  • N0  +  αλ

  • N0

  • λα + N0

  • αλ


233.

Assertion: Nuclei  having mass  number  about  60 are  most stable. 

Reason:  When  two  or  more  light  nuclei  are  combined  into  a  heavier  nucleus, then the binding  energy  per  nucleon  will increase.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


Advertisement

234.

N1 atoms of a radioactive element emit N2 beta particles per second. The decay constant of the element is ( m s-1 )

  • N1/N2

  • N2/N1

  • N1 ( ln2 )

  • N2 ( ln2 )


B.

N2/N1

Number of disintegrations per second      

- dNdt =n =  λN

where λ is decay constant

The negative sign only means that the number of active nuclei decreases with time.

⇒     N2 = λ N1


Advertisement
Advertisement
235.

Assertion:  90Sr from the radioactive fall out from a nuclear bomb ends up in the bones of human beings through the milk consumed by them. It causes impairment of production of red blood cells.

Reason: The energies β-particles emitted in the decay of  90Sr damage the bone marrow.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


236.

What is the amount of energy released by deuterium and tritium fusion?  [ Given: MH12 =2.0141024 u,  MH13 = 3.0160504 ,  Mn01 = 1.0086654 u ]

  • 60.6 eV

  • 12.6 eV

  • 17.6 eV

  • 28.3 eV


237.

What is the energy of photon whose wavelength is 6840 A ?

  • 1.81 eV

  • 3.6 eV

  • - 13.6 eV

  • 12.1 eV


238.

Calculate power output of  U92235 reactor, if it is takes 30 days to use up 2 kg of fuel, and if each fission gives  185 MeV of useable energy. Avogadro's number = 6 × 1023 / mol?

  • 56.3 MW

  • 60.3 MW

  • 58.3 MW

  • 54.3 MW


Advertisement
239.

Assertion: Heavy water is a better moderator than normal water.

Reason: Heavy water absorbs neutrons more efficiently than normal water.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


240.

Assertion:  94Sr from the radioactive fall out from a nuclear bomb ends up in the bones of human beings through the milk consumed by them. It causes impairment of the production of red blood cells. 

Reason: The energetics  β-particles emitted in the decay of  94Sr damage the bone marrow.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false


Advertisement