Question

If light is shined on an atom, usually nothing happens to the atom. Why?

Answer 1

Light consists tiny particles called photons. when light is shined on an atom the light particles called photons gets collided with electrons in side the atom. and thus the electrons due to collision with photons its movementum is changed and gets into conduction.

Answer 2

@M_Vamshi_Kumar_Reddy thank you!!

Answer 3

you are welcome friend.

Answer 4

"its momentum is changed and gets into conduction" ???

that doesn't make any sense :-/

the concept is way more subtle than that.. in reality the simplest thing that can happen is, the electron absorbs that entire photon of energy.. and go to a higher level and then come back down to the lower level and then release the same amount of photon back.. which we at a macroscopic level call as transmission of light!

but then we can have incoherent scattering as well!

Answer 5

@Mashy thanks for you reply!(:

Answer 6

Wait...would we be able to see the transmission of light? or would it look like nothing was happening?

Answer 7

you can't see those things.. they are microscopic interactions that last for nano seconds..!!

Answer 8

If photon is a particle how can we consider photon as energy. when a photon is collided with electron, kinetic energy of photon is acquired by electron and it jumps into various orbits which we generally call it as energy levels. when electron is jumping or moving into higher or lower energy levels,why "its momentum is changed" cant make sense. and photon is not absorbed by electron only its kinetic energy is transmitted when collided.

Answer 9

photon is ABSORBED.. the energy of the photon is used up to transfer the electron to a HIGHER POTENTIAL.. in this case the momentum will not change


when does momentum change? when we have incoherent scattering (raman effect or compton effect)
what happens there?! .. in that case a PART of the energy is lost to the electron as kinetic energy.. but that doesn't put the electron into conduction

if you want to put electron into conduction you need to take it to a higher potential.. like the first case.. like i said.. the concepts are very subtle.. and i cannot justify everything in one post :)

Answer 10

if a photon cant put electron into conduction,. then how solar panels are working? it is all about conservation of movementum. as you said photon is absorbed, As you said photon is absorbed. you must be some clear only its energy is absorbed not photon.
It is like when i push an object with certain force that object absorbs kinetic energy from my hand but it will not make any sense that object is absorbing my hand.

Answer 11

what ?

photon itself is energy.. photon is NOTHING but energy!