0%

DP IB Physics: HL

Topic Questions

Home / IB / Physics: HL / DP / Topic Questions / 7. Atomic, Nuclear & Particle Physics / 7.3 The Structure of Matter / Structured Questions


7.3 The Structure of Matter

Question 1a

Marks: 3

Rutherford used the scattering of α particles to provide evidence for the structure of the atom. The apparatus includes a narrow beam of α particles fired at a very thin sheet of gold foil inside a vacuum chamber.

(a)
Explain why it is essential to use:

(i)
a vacuum in the chamber

[1]

(ii)
a very thin sheet of gold foil    

[1]

(iii)
a narrow beam of alpha particles   

[1]

    Assess your score
      

    Question 1b

    Marks: 3

    The diagram shows α particles incident on a layer of atoms in a gold foil.

    (b)
    On the diagram, draw and complete the paths followed by each of the α particles shown.

    ma1b_7-3_medium_ib-physics

      Assess your score
        

      Question 1c

      Marks: 5
      (c)
      Outline the results of the scattering experiment by explaining:

      (i)
      the main observations of the scattering experiment

      [2]

      (ii)
      the significance of each observation

      [3]

        Assess your score
          

        Question 1d

        Marks: 6

        The Thomson model of the atom preceded Rutherford’s model. In the Thomson model, the atom was imagined as a sphere of positive charge of diameter 10–10 m containing electrons moving within the sphere.

        Thomson’s model could explain some of the results of the Rutherford experiment, but not all.

        (d)
        Explain

        (i)
        why, at small deflections, Rutherford’s experiment can be explained by Thomson’s model but not at large deflections

        [3]

        (ii)
        why Rutherford’s model of the atom can account for the results at both small and large deflections

        [3]

          Assess your score
            

          Question 2a

          Marks: 3

          Electron capture is one of the ways a nucleus attains stability.

          In this process, a proton in the nucleus ‘captures’ an inner-shell electron. While the mass number is unchanged, the atomic number decreases by 1, and a highly energetic particle is released.

          (a)
          Deduce the type of interaction responsible for this process and explain your reasoning.
            Assess your score
              

            Question 2b

            Marks: 4
            (b)
            By writing an appropriate equation for this process and applying the laws of particle physics, identify the highly energetic particle emitted in this process.

              Assess your score
                

              Question 2c

              Marks: 5

              At the quark level, only some are directly involved in this process. Those which are not are sometimes called ‘spectator quarks’.

              (c)
              (i)
              Use your equation to sketch a suitable Feynman diagram for this process.

              [3]

              (ii)
              Sketch another Feynman diagram in terms of the quarks directly involved in electron capture. Do not include spectator quarks.

              [2]

                Assess your score
                  

                Question 2d

                Marks: 2

                A similar process known as muon capture is being investigated for use in the disposal of highly radioactive waste. A highly energetic muon beam causes muons to be captured by protons in the nuclei of the radioactive isotopes in order to convert them into more stable isotopes.

                (d)
                Write the equation and sketch a Feynman diagram for this process.

                  Assess your score
                    

                  Question 3a

                  Marks: 4
                  (a)
                  Compare and contrast the properties of baryons and mesons.
                    Assess your score
                      

                    Question 3b

                    Marks: 4

                    straight capital sigma to the power of 0 is a baryon with a quark structure of u d s.

                    A proposed particle interaction involving the straight capital sigma to the power of 0 baryon is:

                                       space p plus e to the power of plus rightwards arrow e to the power of minus plus capital sigma to the power of 0 plus K to the power of plus

                    (b)
                    Use the principles of conservation of charge, baryon number, lepton number and strangeness to determine whether this decay is possible.
                      Assess your score
                        

                      Question 3c

                      Marks: 3

                      straight capital sigma to the power of 0 is part of a family of baryons called Sigma baryons. They are all strange particles.

                      (c)
                      Determine the quark combination of the straight capital sigma to the power of plus baryon. Clearly show your working
                        Assess your score
                          

                        Question 3d

                        Marks: 4
                        (d)
                        Determine the charge, baryon number, lepton number and strangeness of a particle with the quark combination d d s.

                        Clearly explain your reasoning for each.
                          Assess your score
                            

                          Question 4a

                          Marks: 2

                          The virtual photon mediates the electromagnetic force.

                          It is called a ‘virtual’ photon because it is not detectable in a laboratory.

                          a)
                          Sketch a Feynman diagram to show electrostatic repulsion between two electrons.
                            Assess your score
                              

                            Question 4b

                            Marks: 3
                            (b)
                            Explain why virtual photons cannot be detected in a laboratory but are nonetheless required by particle physics.  
                              Assess your score
                                
                              Key Concepts
                              Fundamental Forces

                              Question 4c

                              Marks: 3

                              The unfinished Feynman diagram shows the interaction between a proton and an anti-neutrino. 
                              q4c_7-3_medium_ib-physics-1

                              (c)        Complete the Feynman diagram.

                                Assess your score
                                  

                                Question 4d

                                Marks: 3

                                The neutron-neutrino interaction can be expressed in a similar way to the Feynman diagram in part (c).

                                d)
                                Describe the changes to the Feynman diagram in part (c) that would show the neutron-neutrino interaction.
                                  Assess your score
                                    

                                  Question 5a

                                  Marks: 2

                                  The Feynmann diagrams show two electroweak interactions between electrons. One of the exchange particles is a photon.

                                   q5a_the-structure-of-atom_ib-sl-physics-sq-medium-3

                                   

                                  a)
                                  (i)
                                  Identify the other exchange particle which isn’t a photon

                                  [1]

                                  (ii)
                                  Outline one difference between the two exchange particles

                                  [1]

                                    Assess your score
                                      

                                    Question 5b

                                    Marks: 2
                                    b)
                                    Outline how interactions in particle physics are understood in terms of exchange particles.
                                      Assess your score
                                        
                                      Key Concepts
                                      Exchange Particles

                                      Question 5c

                                      Marks: 2
                                      (c)
                                      Describe the significance of the Higgs Boson in the standard model of quarks and leptons.
                                        Assess your score
                                          
                                        Key Concepts
                                        The Higgs Boson

                                        Question 5d

                                        Marks: 3

                                        The discovery of the Higgs Boson marked a huge accomplishment for particle physicists.

                                        It was first hypothesised by Peter Higgs and his team in 1964 and then discovered by a large collaborative effort at the CERN particle physics laboratory much later in 2012.

                                        (d)
                                        Explain what is meant by the term ‘hypothesised’ and suggest why it took over forty years to discover the Higgs Boson.
                                          Assess your score