A mono-chromatic point source S radiating wavelength with power
an aperture A of diameter 0.1 metre and a large screen Sc are placed as shown in figure. A photo emission detector D of surface Area
is placed at the centre of the screen. The efficiency of the detector for the photo-electro generation per incident photon is 0.9
Question:
Light from a discharge tube containing hydrogen atoms falls on the surface of a piece of sodium. The kinetic energy of the fastest photo-electrons emitted from sodium is 0.73 eV. The work function for sodium is 1.82 eV. Then the energy of the photons causing photoelectric emission is:
1.55 eV
1.95 eV
2.05 eV
2.55 eV
According to Einstein’s photo-electric equation, the maximum kinetic energy EK of the emitted electrons is given by
where is the energy of photons causing the photo- electric emission and W is the work-function of the emitting surface.