K.C.S.E Physics Q & A - MODEL 2002PP2QN07

K.C.S.E Physics Q & A - MODEL 2002PP2QN07

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​a) Fig. 8 shows ultra violet light striking a polished zinc plate placed on a negatively charged gold – leaf electroscope.

​Explain the following observations
i) The leaf of the electroscope falls.
ii) When the same experiment was repeated with a positively charged electroscope the leaf did not fall.
bi) State two factors which determine the speed of photoelectrons emitted by a metal surface
ii) In an experiment using a photocell, u, v. light of varying frequency but constant intensity was made to strike a metal surface. The maximum kinetic energy (K.E max)of photoelectrons for each frequency, was measured. The graph shows how KE max varies with f

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