question_answer

Electrons are emitted from a photo-sensitive 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 (i) red light, and (ii) blue light?         

Answer:

                (i) No, electrons are not emitted by yellow light, because \[{{v}_{red}}{{<}_{yellow}}\] (ii) Yes, electrons are emitted by blue light, because \[{{v}_{blue}}>{{v}_{green}}\]