Themes > Science > Physics > Quantum Physics > Quantum theory of light > Wave-Particle Duality > Experimental Observations

a. Not one electron is emitted if the frequency of the light is below a certain value (called the "threshold frequency", which is dependent on the type of the metal). Above this threshold frequency, the maximum energy of the emitted electrons increases in direct proportion to the frequency of the light.

b. The maximum energy of the emitted electrons is independent of the intensity of the light.

c. No matter how weak the light, as long as its frequency is above the threshold frequency, the emission of electrons starts IMMEDIATELY the light is switched on.

(In case you were wondering; an increase in the light intensity increases the number of electrons emitted per second, while leaving the energy of each electron unchanged).


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