# Modern Physics, Finding wave length problem! wee

Modern Physics, Finding wave length problem! wee!!

Ello ello!
I'm having troubles getting this table started. The directions are:
Use the Bohr diagram shown below to complete the following table.

Tell the wavelength and color of light emitted when the following energy level changes occur.
Orbital change
n = 4 to n = 1
Wavelength = ?

Color/Type
Select:
red/UV/green/IR/blue

Well once i find the wave length i'm pretty sure i can just look at the table, and find the correct color it corresponds too.

So if n = 4, that looks like its pointing to the UV spectrum, but what are those numbers under it? such as: 397 389 etc

So it goes to n =1, that means it is going to give off light. and n =1 looks lkike its still in the UV spectrum. so would i take the wave lengths:
397 - 389 = 8nm? i'm assuming those numbers are in nano meters. So the color type would be UV which i got right. But i'm still confused on the wave length. I subbmited 8nm as my answer and it was wrong.Any help would be great!

Related Introductory Physics Homework Help News on Phys.org
dav2008
Gold Member
In the circular diagram, there is an arrow that signals the n=4 to n=1 transition. The arrow signifies the photon that is emitted when an electron drops from the n=4 to n=1 state.

Yes the numbers are the wavelength in nanometers.

Doc Al
Mentor
mr_coffee said:
Well once i find the wave length i'm pretty sure i can just look at the table, and find the correct color it corresponds too.
Just follow the arrows; they point to the wavelength of the photon emitted for each transition.

So if n = 4, that looks like its pointing to the UV spectrum, but what are those numbers under it? such as: 397 389 etc
Each line in the spectrum has its wavelength listed.

So it goes to n =1, that means it is going to give off light. and n =1 looks lkike its still in the UV spectrum. so would i take the wave lengths:
397 - 389 = 8nm? i'm assuming those numbers are in nano meters. So the color type would be UV which i got right. But i'm still confused on the wave length. I subbmited 8nm as my answer and it was wrong.Any help would be great!
No need to subtract anything. Find the n = 4 to 1 transition, follow the arrow, then read off the wavelength.

thanks guys that worked for the first, the answer was: 389 nm, and it was UV. I just looked at n4 and followed the arrow to the 389.
but i went onto the next one which is:
n = 4 n = 2, i wrote down the wave length of the n = 2, and the n =4, both wrong and its also saying its not even UV light anymore. But if u follow the arrows n = 2, and n = 4 are both in the UV. Any ideas what i'm misinterpreting? thanks!

Doc Al
Mentor
A wavelength corresponds to a transition between two levels, so to say that you found the wavelength for n = 2 or n = 4 doesn't make sense. Find the arrow that shows the electron falling from n = 4 to n = 2; that's the one you want.

Oo i got what your saying now! thanks a ton Doc!