# If you know the wavelength of light emitted by a laser how can you know

1. Apr 20, 2010

### kashiark

1. The problem statement, all variables and given/known data
How can you know "the difference between the two lasing energy levels?"

2. Relevant equations
n(lambda) = 2(pi)r
E = hf
mvr = n(h-bar)
3. The attempt at a solution
no clue

2. Apr 20, 2010

### kuruman

You know that E = hf. How is the the frequency related to the wavelength?

3. Apr 20, 2010

### kashiark

I know how to find the energy of the given wavelength, but how do I find the other lasing energy level? What is a lasing energy anyway, and why are there 2?

4. Apr 20, 2010

### kuruman

You are looking for the difference between energy levels. How is the difference related to the emitted photon energy?

5. Apr 20, 2010

### aabdella

If u r talking abt 2 levels laser, then the emitted photon energy is the same as the difference between th two lasing levels

6. Apr 20, 2010

### kashiark

The two are equivalent; so the lasing energy levels are just the levels that the electrons jump to release the photon?

7. Apr 20, 2010

### kuruman

Yup.

8. Apr 20, 2010

### kashiark

That's simple enough; I was just confused over the terminology; thanks!