Hint
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Answer
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What happens in terms of quarks during beta minus decay
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A down quark (in a neutron) turns into an up quark (in a proton)
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What happens in terms of quarks during beta plus decay
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An up quark (in a proton) turns into an down quark (in a neutron)
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When is strangeness conserved?
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Strong interaction
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The energy of a photon is inversely proportional to…?
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Wavelength
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Define threshold frequency
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The minimum frequency of light required to produce photoelectrons
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Define work function of a metal
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The minimum energy required to remove an electron from the surface of the metal
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How do you calculate the threshold frequency from the work function?
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Divide the work function by Planck's constant
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What happens to the photon energy if frequency is doubled?
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Doubled
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What happens to the number of photoelectrons per second if the intensity of light remains the same but frequency is doubled?
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Halved
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What happens to the photoelectrons produced if the intensity of a light source is increased but the frequency is constant?
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More photoelectrons will be produced but they will have the same maximum kinetic energy
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Why does the kinetic energy of photoelectrons from monochromatic light vary in the photoelectric effect?
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The work function is a minimum energy. Some electrons require more energy to be liberated.
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Define the ground state of an atom
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The lowest energy level an electron can occupy
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Define ionisation
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The addition or removal of an electron from a neutral atom.
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Define ionisation energy
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The energy required to remove an electron that is in the ground state of an atom.
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Define excitation of an atom
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The atom gains energy and an electron moves up to a higher energy level.
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Which processes can lead to the excitation of an atom
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A collision with a charged particle ,The absorption of a photon by an electron in the atom.
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Describe the de-excitation of an atom
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An electron moves down energy levels and emits a photon
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What two variables determine the De Broglie wavelength of a particle?
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Mass and velocity
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Which key piece of evidence that demonstrated the validity of De Broglie's matter-wave hypothesis?
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Electron diffraction through a thin metal foil
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A photon can ionise an atom if its energy is greater than …?
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the ionisation energy
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Two factors that determine the maximum kinetic energy of photoelectrons are…?
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The frequency of the light and the work function of the metal
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A photon can produce a photoelectron if its frequency is greater than
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the threshold frequency
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