How many times does a atom excitate when light shines onto it?

[whattahw]

Noob question ahead.

So basically I'm reading about atoms and photons in my textbook at the moment and I came across excitation and why atoms emit photos with certain wavelengths when hit by white light. The claptrap doesn't really matter, what I'm confused and curious about is how many times does an atom "excite" every second when light shines onto it.

I've understood that when photos hit an atom, i.e. hydrogen the electrons around the nucleus gets excited and jumps up one energy level(orbital), and when they "fall" down again, the difference in energy is what gets emitted as a photon. This is the part that I am curious about. If a 1000 photos hit an atom a second does that basically mean that the single atom gets excited 1000 times and emits 1000 photos with the wavelength that accompanies that change in energy.

Please help, thank you.

 

[M Quack]

Try to estimate how many photons you shine onto your sample per, say, 1 second.

Then try to estimate how many atoms the photons are illuminating.

The ratio is the maximum average number of excitations. There will be a statistical distribution, of course, so some atoms get excited more often than others. But at least this gives you a ballpark number. Also, this assumes that every photon that his the sample actually excites an atom. This is not always the case.

The fewer atoms you have, e.g. if you decrease the pressure in a gas, the smaller is the chance that a photon "hits" an atom and excites it. Most photons will simply be transmitted without interacting with the atoms.

 

[whattahw]

Sorry for the very late response, but forgot about this and been busy. If you do have the patience though, could you please link me to the formula for calculating photos per second. In my book, they expect you to manipulate and use the wave formula together with the formula for wavelength energy formula or something, here; E = h * f
Nowhere in the book does it say how to do this, but I tried manipulating the formulas a tiny bit and noticed that it has something to do with the Planck constant, but my answers seem rather inconsistent, but please correct me thank you.

 

[Drakkith]

The answer to your question depends on at least two things:

1. How likely the atom is to be excited by a passing photon.
2. How long it takes for the excited state to decay.

If your atom simply doesn't have time to decay from its excited state before the next photon "hits", then it won't absorb the photon. The amount of time an atom remains in an excited state can be very different for different states, so there is no single answer to your question.

 

[sardar]

Great question! When light shines onto an atom, the number of times it gets excited depends on the intensity and frequency of the light, as well as the properties of the atom itself. In general, an atom can be excited multiple times by a single photon if the energy of the photon is greater than the energy needed to excite the atom. However, the exact number of times an atom gets excited can vary.

For example, in the case of hydrogen, a single photon with enough energy can excite the electron from its ground state to a higher energy level. When the electron falls back down to its ground state, it will emit a photon with a specific wavelength. This process can happen multiple times if the atom is exposed to multiple photons with the same energy.

However, the number of times an atom gets excited can also depend on the energy levels of the atom and the energy of the photons. In some cases, the energy of a photon may not be enough to excite the electron to a higher energy level, so the atom will not get excited. Additionally, some atoms have multiple energy levels, so they can get excited to different levels depending on the energy of the photon.

In summary, the number of times an atom gets excited when light shines onto it can vary depending on the intensity and frequency of the light, as well as the properties of the atom itself. It is not always a one-to-one ratio, and the exact number of excitations can depend on various factors.