12th Class Physics Nuclear Physics And Radioactivity Question Bank

done MCQs - Nuclei Total Questions - 11

• question_answer1)
  The gravitational force between a H-atom and another particle of mass m will be given by Newton's law: \[\operatorname{F}=G\frac{M.m}{{{r}^{2}}}\] where r is in km and
  A)
  \[M={{m}_{\operatorname{proton}}}+{{m}_{\operatorname{electron}}}\]  done clear
  B)
  \[M={{m}_{\operatorname{proton}}}+{{m}_{\operatorname{electron}}}-\frac{B}{{{c}^{2}}}\]    \[(B=13.6ev)\] done clear
  C)
  M is not related to the mass of the hydrogen atom. done clear
  D)
  \[M={{m}_{\operatorname{proton}}}+{{m}_{\operatorname{electron}}}-\frac{|V|}{{{c}^{2}}}(|V|=\]magnitude of the potential energy of electron in the H-atom). done clear
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• question_answer2)
  Heavy stable nucleus have more neutrons than protons. This is because of the fact that
  A)
  neutrons are heavier than protons. done clear
  B)
  electrostatic force between protons are repulsive. done clear
  C)
  neutrons decay into protons through beta decay. done clear
  D)
  nuclear forces between neutrons are weaker than that between protons. done clear
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• question_answer3)
  Tritium is an isotope of hydrogen whose nucleus Triton contains 2 neutrons and 1 proton. Free neutrons decay into p + e + v. If one of the neutrons in Tritium decays, it would transform into \[_{2}{{\operatorname{He}}^{3}}\] nucleus. This does not happen. This is because
  A)
  tritium energy is less than that of a \[{{\operatorname{He}}^{3}}\] nucleus. done clear
  B)
  the electron created in the beta decay process cannot remain in the nucleus. done clear
  C)
  both the neutrons in triton have to decay simultaneously resulting in a nucleus with \[{{\operatorname{He}}^{3}}\] protons, which is not a  nucleus. done clear
  D)
  because free neutrons decay due to external perturbations which is absent in a triton nucleus. done clear
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• question_answer4)
  Nuclear force is a _______ and _______ force.
  A)
  Strong, long-range done clear
  B)
  Strong, short range done clear
  C)
  Weak, long-range   done clear
  D)
  Weak, short-range done clear
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• question_answer5)
  Two nuclei have mass number in the ratio 1:2. The ratio of their nuclear densities is
  A)
  1:2 done clear
  B)
  2:1 done clear
  C)
  1:1 done clear
  D)
  Cannot be denned from mass number ratio done clear
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• question_answer6)
  The mass of a nucleus in its ground state is
  A)
  less than the total mass of neutrons and protons. done clear
  B)
  greater than the total mass of neutrons and protons. done clear
  C)
  equal to the total mass of neutrons and protons. done clear
  D)
  equal to the total mass of neutron, protons and electrons. done clear
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• question_answer7)
  _________ has the mass closest to the mass of positron.
  A)
  Proton  done clear
  B)
  Neutron done clear
  C)
  Electron   done clear
  D)
  Neutrino done clear
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• question_answer8)
  X amount of energy is required to remove an electron from its orbit and Y amount of energy is required to remove a nucleon from the nucleus.
  A)
  X = Y done clear
  B)
  X > Y done clear
  C)
  Y>X   done clear
  D)
  X \[\ge \] Y done clear
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• question_answer9)
  Suppose we consider a large number of containers each containing initially 10,000 atoms of a radio-active material with a half-life of 1 year. After 1 year.
  A)
  all the containers will have 5,000 atoms of the material. done clear
  B)
  all the containers will contain the same number of atoms of the material but that number will only be approximately 5,000. done clear
  C)
  the containers will in general have different numbers of the atoms of the material but their average will be close to 5,000. done clear
  D)
  none of the containers can have more than 5000 atoms. done clear
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• question_answer10)
  Consider the following reaction: \[{}_{Z}^{A}\operatorname{X}\to {}_{Z+1}^{A}\operatorname{Y}\to {}_{Z-1}^{A-4}\operatorname{Z}\to {}_{Z-1}^{A-4}\operatorname{Z}\] Radioactive radiation emitted in the following sequence:                                  
  A)
  \[\beta ,\alpha ,\gamma \]  done clear
  B)
  \[\alpha ,\beta ,\gamma \]   done clear
  C)
  \[\gamma ,\beta ,\alpha \]   done clear
  D)
  \[\beta ,\gamma ,\alpha \]            done clear
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• question_answer11)
  Which of the following material will be the best moderator for a nuclear power plant?
  A)
  Lighter element   done clear
  B)
  Heavier element  done clear
  C)
  Both of the above done clear
  D)
  None of the above done clear
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