# How colored light can be explained if light is considered as emission of photon?

If light is considered as wave, then different colored light can be explained as waves of different wavelength/frequency. How colored light can be explained if light is considered as emission of photon?

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The Energy of the Photon defines its frequency. It is the equation $$E=h\nu$$ which puts this in mathematical terms. Where $h$ is Planck's constant, $E$ the Energy and $\nu$ the frequency. This can also be written in terms of wavelength of the photon as $$E=\frac{hc}{\lambda}$$ So blue (high frequency, short wavelength) light has high energy, red (low frequency, large wavelength) has lower energy

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i can't connect waves and particles. aren't photons travel in straight line? if something travels in straight line, how frequency/wavelength can be defined? –  Donotalo Aug 25 '11 at 12:19
I'd suggest you read through this Wikipedia article en.wikipedia.org/wiki/Wave%E2%80%93particle_duality and in case more Questions arise, ask them here –  luksen Aug 25 '11 at 12:22
Your followup question is essentially equivalent to "How does quantum physics work?" Needless to say, this is an excellent question, but it's not an easy one to give a quick answer to! –  Ted Bunn Aug 25 '11 at 13:45
@Ted Bunn: ok, i'll check them out. thanks. –  Donotalo Aug 25 '11 at 16:09