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(i) Reduce/ prevent collisions of electrons with air molecules and hence increase current
(ii) Control/ limit current, lowers current
(iii) The energy of the radiation must be greater than the work function of the emitting surface.
(iv) Current flows when uv falls on the cathode; interruption of the uv beam cuts off the circuit: use with relay to switch on a second circuit with alarm.
Wilfykil answered the question on March 27, 2019 at 09:08
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