# Can someone teach me for this?

1. Jan 9, 2010

### 54088

Figure 1 shows part of an energy level diagram for a hydrogen atom.

n=4 ------ -0.85eV
n=3 ------ -1.50eV
n=2 ------ -3.40eV
n=1 ------ -13.60eV

When an electron of energy 12.1eV collides with the atom, photons of three different energies are emitted.
[a] on Figure 1 show with arrows the transitions responsible for these photons.

> ????

Calculate the wavelength of the photon with the smallest energy. Give your answer to an appropriate number of significant figures.

>(E = hcl入)
>energy in joules = (??) x 1.6 x 10^-19 = (????)(J)

2. Jan 9, 2010

### diazona

I think this should be in the homework forum. Someone will probably move it for you. (Whoever does can delete this post)

3. Jan 9, 2010

### 54088

Hi, this is not my homework, im revising Physics at the moment, im stuck with this question.

4. Jan 9, 2010

### mensa

I've forgot most of atomic physics. But I can show u the process.
[a]at first n=1,then comes the electron with 12.1eV,so the energy raises from -13.6 to -1.5,and n=3.Energy always wants to go from the high level to the low level,and at this time we have 3 ways,that is 3->2,2->1,3->1,these are the "photons of three different energies"
then is easy

5. Jan 9, 2010

### 54088

---------------------
---------------------
↓ .......↓
---------------------
↓.................↓
---------------------
↓.................↓
---------------------

Is it kindda look like this......?

6. Jan 10, 2010

### mensa

I'm sorry I wasn't here.
But I can't catch your point.
What I said means,at first n=1,after 12.1eV comes,n=3. n=3 has 3 ways to go as following
goto 2,releasing 1.9eV
goto 1,releasing 12.1eV
but after 3 go to 2,we still have a 2,and this 2 can goto 1,releasing 10.2eV

7. Jan 10, 2010

### ideasrule

Alright, I'm super confused by this point. To the OP: can you upload figure 1? Where are the arrows?