Find the wavelengths Kα, Kβ , Lα and Lβ from elemental Cu

[AlphaLibrae]

Homework Statement

Problem: "What are the wavelengths of the characteristic Kα, Kβ , Lα and Lβ x-rays emitted from copper? Remember to use a Rydberg constant with the reduced mass correction made for elemental copper."

Givens:
Energy levels given:

Kα (2,1)

Kβ (3, 1)

Lα (3, 2)

Lβ (4, 2)​

Prompt and energy levels here: https://imgur.com/ygtSCWx

Homework Equations

No relevant equations were provided for this assignment. The prompt hinted to use the Rydberg formula, but since I took into account the mass correction for elemental copper was made. I used the following equation:

1/λ=RZ^2((1/n^2)−(1/n^2))

The Attempt at a Solution

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For LB (2,1), here is how I calculated the wavelength.

1/λ=RZ^2((1/n^2)−(1/n^2)) = (1.09737*10^7) * ((1/2^2) - (1/4^2))

λ = 0.14 nm

However, WebAssign has marked this wrong. Any suggestions?

 

[mjc123]

Why did you use 2 and 4 for the n values? What value did you use for Z?

 

[AlphaLibrae]

Why did you use 2 and 4 for the n values? What value did you use for Z?

Sorry, meant to say Lβ (4, 2) .For Z, I used 29.

 

[mjc123]

How did you get such wildly different numbers for the 4 lines (including one negative)?