## Mashy 3 years ago planks quantum theory E= hf, what is f? Ok i know f is the frequency of the radiation, but when we see it as a particle, what exactly is f?? we cannot use cycles per second, cause thats the definition of a wave, in particle nature, there is no cycle.. but only photons.. so what exactly if f?

1. Mashy

2. JamesJ

f is the frequency of the photon when considering it as a wave. In short, EM radiation is neither exclusively a wave or a particle, but exhibits the behavior of both. This equation is a perfect example of where insisting its one or the other is not productive. A photon is a discrete quanta of energy. It's energy is given by Plank's equation E = hf. You must accept that both the wave and particle properties are here in play.

3. Mashy

but... when we consider this equation we talk about ONLY particle property of light.. and then we use this equation along with e= mc squared.. and de broglie gets the credit for constructing dual nature. how so?..

4. Mashy

sorry de broglie gets credit for saying even matter should have wave.. however, when we study theories of light, we say plancks quantum equation talks about particle property.. why don't they say.. plancks equation is actually a dual nature itself??

5. JamesJ

With respect to your last question: the reason that the particle nature of light is emphasized with the formulation E = hf is normally because it's introduced to students when discussing the photoelectric effect. This effect very importantly cannot be explained using the wave interpretation of light and is one of the main reasons we have the particle model at all. So the essential interaction that explains the photoelectric effect is this quantized, particle-like nature of the energy of the EM radiation.

6. Mashy

So its possible to independently define wave nature of light, but its not possible to do the same for particle nature .. am i right?

7. JamesJ

I wouldn't think of it that way. Light is sometimes wave like (e.g., Young double slit experiment); sometimes particle like (e.g., photoelectric effect) The exact relations of energy are of course mixed up, because light is neither one nor the other.

8. Mashy

yes .. m still not satisfied.. lets not talk about dual nature for a while, when quantum theory was devised it is supposed to support ONLY PARTICLE nature of light.. so that theory shouldn't have anything to do with wave.. like how EM theory has nothing to do with quantum theory!