# Calculate the frequency, in hertz (level n = 10 to level n = 5)

1. Sep 19, 2009

### pinklemon

Calculate the frequency, in hertz, of the photon that is emitted when a electron falls from level n = 10 to level n = 5 in the H atom.

Enter a numeric answer only, no units.

I tried asking in other places but ppl are so ambiguous about it.

I used rydberg formula:
1/λ = RH ∙ (1/n₁² - 1/n₂²)
(RH rydberg constant for hydrogen, n₁ lower level, n₂ higher level)

Hence:
λ = 1/ [ 1.09678×10⁷m⁻¹ ∙ (1/5² - 1/10²) ] = 3.0392×10⁻⁶m

and then I converted to Hz = 9.89e14 but i still GOT IT wrong :( Please help me someone!!!

2. Sep 19, 2009

### elduderino

The above calculation is done for a hydrogen atom. Check the problem to see if a different Z is given. (the factor of $$Z^2$$is added to the rydberg equation for approximating photon frequencies of hydrogen-like atoms with a different atomic number.

3. Sep 19, 2009

### pinklemon

I don't understand. So there's another Z? But I thought it is only 5 and 10?

oh dear. i think i posted in the wrong section.