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10.1 A learner is investigating the photoelectric effect for two different metals, silver and sodium, using light of different frequencies. The maximum kinetic energy of the emitted photoelectrons is plotted against the frequency of the light for each of the metals, as shown in the graphs below.
10.1.1 Define the term threshold frequency. (2)
10.1.2 Which metal, sodium or silver, has the larger work function?
Explain the answer. (3)
10.1.3 Name the physical constant represented by the slopes of the graphs. (1)
10.1.4 If light of the same frequency is shone on each of the metals, in which metal will the ejected photoelectrons have a larger maximum kinetic energy? (1)
10.2 In a different photoelectric experiment blue light obtained from a light bulb is shone onto a metal plate and electrons are released.
The wavelength of the blue light is 470 x 10-9 m and the bulb is rated at 60 mW. The bulb is only 5% efficient.
10.2.1 Calculate the number of photons that will be incident on the metal plate per second, assuming all the light from the bulb is incident on the metal plate. (5)
10.2.2 Without any further calculation, write down the number of electrons emitted per second from the metal. (1)
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TOTAL: 150