## Exercise A15

H-Atom ($E_{n}=-\frac{hR}{n^{2}}$)

yast_27
Posts: 29
Joined: Fri Sep 28, 2018 12:19 am

### Exercise A15

Hi,

I've worked on this exercise but i'm not sure that my way to approach the problem is the correct one.

"In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6nm. Determine the values of n for the initial and final energy levels of e- during the emission of energy that leads to this spectral line"

I use this equation:

Ephoton= E1-E2
h*C/ƛ = hR*(1/(n2^2) - 1/(n1^2))
and after filling the value that i have, i just try different value of n until i find the right one.
Is this the right way to approach this problem?

Thank you for your help! :)

Nicole Elhosni 2I
Posts: 62
Joined: Fri Sep 28, 2018 12:28 am

### Re: Exercise A15

Okay, because it is the hydrogen atom and it is known to be in the UV region (aka Lyman Series), we know that the final energy level will be 1.
Given the 102.6 x 10^-9 m, we can use wavelength x frequency = speed to find the frequency. From this we can use the frequency and multiply it by Plank's Constant to calculate Energy. This energy will be the energy of the light given off.
From there, we can set up an equation using the energy levels and set them equal to the Energy we just calculated; E= (-hR/n²)
So it will be (-hR/1²) - (-hR/n²) = Energy calculated
From there, it will become an algebra problem to solve for n², where n is the initial energy level.