Question

Electrons are emitted when a photosensitive surface 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
a) red light
b) blue light

Answer 1

Ejection of electrons will be possible by radiations of wavelength less than that of green light.
Because, ${\lambda }_b<{\lambda }_g$
The wavelength of blue light is less than the wavelength of green light.