Photoelectric effect

PHOTOELECTRIC EFFECT

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• Caption: EMISSION OF PHOTOELECTRONS DUE TO PHOTONS INCIDENT ON THE SURFACE OF A METAL
• PHOTONS OF A FREQUENCY AND ENERGY ABOVE THE THRESHOLD FREQUENCY AND WORK FUNCTION OF THE METAL INTERACT ON A ONE-TO-ONE BASIS WITH THE FREE ELECTRONS IN THE METALLIC BINDING OF THE ATOMS IN THE METAL. THIS EXCITES THE ELECTRONS TO A STATE WHERE THEY ARE EJECTED FROM THE METAL.

LIGHT AS A PARTICLE

• PHOTONS INTERACT WITH ELECTRONS IN THE METAL ON A ONE TO ONE BASIS, PROVIDING EVIDENCE FOR THE PARTICLE NATURE OF LIGHT. EINSTEIN SUGGESTED THAT PARTICLES ARE QUANTS OR PACKETS OF LIGHT WHICH ARE MORE COMMONLY KNOWN AS PHOTONS.
• IF LIGHT WAS A WAVE WE WOULD EXPECT THE PHOTOELECTRON EMISSION TO BE DIRECTLY PROPORTIONAL TO THE LIGHT INTENSITY INSTEAD OF THE FREQUENCY. ONLY ONCE ABOVE THE THRESHOLD FREQUENCY AND WORK FUNCTION IS THE NUMBER OF ELECTRONS EMITTED PROPORTIONAL TO THE INTENSITY OF LIGHT, OR NUMBER OF PHOTONS PER SECOND. THE KINETIC ENERGY OF THESE ELECTRONS IS DEPENDENT ON THE PHOTON ENERGY AS ALL OF THE ENERGY OF THE PHOTON IS TRANSFERRED TO THE ELECTRON.