I am very confused about emission specta/color. On one hand, we know that when a

Question

I am very confused about emission specta/color. On one hand, we know that when an atom absorbs a photon of light, the electrons are are excited, lets say, from n=1 to n=2. Subsequently, the electron falls back down from n=2 to n=1, and in doing so, releases a photon OF THE EXACT SAME ENERGY AS THE ONE IT ABSORBED. So then why do we not say that the color an object absorbs is the color we see?

why do we instead say that the color we see, the color "reflected" is the opposite of the color absorbed?? Why do we say that the black parts in an emission spectra of hydrogen, for example, are the colors ABSORBED. Wouldnt it be the opposite? Am I mixing up two concepts?

Explanation / Answer

you are just mixing two concepts...actually the energy absorbed may not be same with the colour emmited..we can explain it with an atom say HYDROGEN.

If A Hydrogen atom absorb energy and the valance shell electron will jump to the higher enegy state...the higher energy state may be n=2,3,4,5,6...It will depend on the enegy absorbed.Say the electron jumps form n=1 to n=5.But when it returns to the lower energy state it radiates energy.Now the electron can jump form n=5 to any of the orbital n=1,2,3,4.The amount of emmited energy will depend upon the orbital to which it returns form n=5.

if it returns form n=5 to n=1 absorbed energy=emmited energy (many of cases this does not lie in visible range)

But if it returns form n=5 to n=2,3,4 absorbed energy is not equal to emmited energy..and we can only see the colours of emmited energy ( in between 400nm to 800nm)..so,the colour reflected is the opposite of the colour absorbed not exactly the colour absorbed.

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