Electrons are emitted from a photosensitive surface when it is illuminated by green light but electron emission does not take place by yellow light. Will the electrons be emitted when the surface is illuminated by (1) red light, and (ii) blue light?

(1) Electrons will not be emitted with red light because its frequency is lower than green and yellow light, providing insufficient energy.
(2) Electrons will be emitted with blue light as its frequency is higher than green light, exceeding the threshold frequency.

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