{"id":111,"date":"2017-03-07T12:08:08","date_gmt":"2017-03-07T12:08:08","guid":{"rendered":"https:\/\/blogs.glowscotland.org.uk\/gc\/advancedhigher\/?page_id=111"},"modified":"2017-03-07T14:58:33","modified_gmt":"2017-03-07T14:58:33","slug":"quantum-physics","status":"publish","type":"page","link":"https:\/\/blogs.glowscotland.org.uk\/gc\/advancedhigher\/quantum-physics\/","title":{"rendered":"Quantum Physics"},"content":{"rendered":"

Quantum Physics<\/u><\/p>\n

 <\/p>\n

1.(a) Explain qualitatively how the Bohr Model of the atom can account for line\u00a0emission spectra.<\/p>\n

 <\/p>\n

(b) It is possible to calculate a de Broglie wavelength for a moving object.<\/p>\n

 <\/p>\n

A ball of mass 45g has a speed of 68ms-1<\/sup>.<\/p>\n

 <\/p>\n

(I) Calculate the de Broglie wavelength for the ball.<\/p>\n

 <\/p>\n

(ii) Explain why wave-like properties are not observed for the ball.<\/p>\n

 <\/p>\n

    \n
  1. (a) State what is meant by the Uncertainty Principle in relation to the position and\u00a0momentum of a subatomic particle.<\/li>\n<\/ol>\n

     <\/p>\n

    (b) An athlete has a mass of 70 kg. At the finish line the position of the athlete has an uncertainty of 1.0 x 10-3 <\/sup>m. Calculate the minimum uncertainty in the momentum of the athlete at the finish line.<\/p>\n

     <\/p>\n

    (c) It takes about 1.6 X 10-13 <\/sup>J of energy to create an electron-positron pair.<\/p>\n

    For what approximate period of time can this amount of energy be borrowed before it has to be paid back by electron-positron annihilation?<\/p>\n

     <\/p>\n

      \n
    1. (a) Bohr\u2019s model of the hydrogen atom includes assumptions about the orbiting electron. One of these is that the electron moves in a circular orbit centred on the nucleus.<\/li>\n<\/ol>\n

       <\/p>\n

      (j) State briefly one of the other assumptions.<\/p>\n

       <\/p>\n

      (ii) By considering the electron as a point mass m travelling around the nucleus, show that the radii of the allowed orbits rn<\/sub> are given by<\/p>\n

      \"\"<\/a><\/p>\n

      where the symbols have their usual meanings.<\/p>\n

       <\/p>\n

      (iii) Calculate the speed of an electron in the first allowed orbit of radius 5.3 x 10-11 <\/sup>m.<\/p>\n

       <\/p>\n

      (b) Planck and Einstein suggested that electromagnetic radiation exhibits a wave-particle duality. De Broglie extended this idea to matter.<\/p>\n

       <\/p>\n

      (i) Write down an expression for the wavelength \u03bb associated with a particle that has a momentum of magnitude p.<\/p>\n

       <\/p>\n

      (ii) (A) A woman of mass 50kg walks through a doorway at a speed of 1.5 ms-1<\/sup>. Calculate her de Broglie wavelength.<\/p>\n

       <\/p>\n

      (B) Explain why the effect of diffraction is negligible when the woman passes through the doorway.<\/p>\n

       <\/p>\n

        \n
      1. (a) Electrons can exhibit wave-like behaviour. Give one example of evidence which supports this statement.<\/li>\n<\/ol>\n

         <\/p>\n

        (b) The Bohr model of the hydrogen atom suggests a nucleus with an electron occupying one of a series of stable orbits.<\/p>\n

         <\/p>\n

        A nucleus and the first two stable orbits are shown below.<\/p>\n

        \"\"<\/a><\/p>\n

        (i) Calculate the angular momentum of the electron in the second stable orbit.<\/p>\n

         <\/p>\n

        (ii) Starting with the relationship<\/p>\n

        \"\"<\/a><\/p>\n

        show that the circumference of the second stable orbit is equal to two electron wavelengths.<\/p>\n

         <\/p>\n

        (iii) The circumference of the second stable orbit is 1.3 x 10-9<\/sup> m. Calculate the speed of the electron in this orbit.<\/p>\n

         <\/p>\n","protected":false},"excerpt":{"rendered":"

        Quantum Physics   1.(a) Explain qualitatively how the Bohr Model of the atom can account for line\u00a0emission spectra.   (b) It is possible to calculate a de Broglie wavelength for a moving object.   A ball of mass 45g has a speed of 68ms-1.   (I) Calculate the de Broglie wavelength for the ball.   … Continue reading Quantum Physics<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":6460,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-111","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/advancedhigher\/wp-json\/wp\/v2\/pages\/111","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/advancedhigher\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/advancedhigher\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/advancedhigher\/wp-json\/wp\/v2\/users\/6460"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/advancedhigher\/wp-json\/wp\/v2\/comments?post=111"}],"version-history":[{"count":6,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/advancedhigher\/wp-json\/wp\/v2\/pages\/111\/revisions"}],"predecessor-version":[{"id":127,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/advancedhigher\/wp-json\/wp\/v2\/pages\/111\/revisions\/127"}],"wp:attachment":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/advancedhigher\/wp-json\/wp\/v2\/media?parent=111"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}