question_answer

When a monochromatic yellow coloured light beam is incident on a given photosensitive surface, photoelectrons are not ejected, while the same surface gives photoelectrons when exposed to green coloured monochromatic beam. What will happen if the same photo-sensitive surface is exposed to (i) violet and (ii) red coloured, monochromatic beam of light? Justify your answer.                 

Answer:

                (i) Violet light has higher frequency than green light, so it can eject electrons from the photosensitive surface. (ii) Red light has lower frequency than yellow light, it cannot eject electrons from the photo-sensitive surface.