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Example photoelectric questions:

1.      (a) Describe a simple experiment by which the photoelectric effect may be demonstrated.    


      (b) Explain what is meant by

             (i) a photon,

             (ii) work function.

             How do these two concepts explain that:

      (iii) the number of electrons emitted is proportional to the intensity of the radiation incident upon a clean metal surface,

      (iv) these electrons are emitted with a range of velocities from zero up to a maximum value which increases with the frequency of the incident radiation but is independent of the intensity,

  (v) there is, for each metal, a certain minimum frequency below which no emission occurs.           


      (c) Give a brief description of a use to which the photoelectric effect is put.


(AEB, question B16, paper 3, June 1982)

2.   (a)  Explain the term "wave / particle duality"

      (b)  (i) Discuss the experimental evidence that suggests that electromagnetic  radiation is quantized.

            (ii) A beam of electrons has a speed equal to 5x106 ms-1.  Use de Broglie's duality expression to suggest a possible way in which the wave properties of the electron could be demonstrated.  (Take the mass of the electron as 9.0 x 10-31 kg