K alpha and K beta wavelengths

In summary: V - 1s) = 1.534 x 10^-11 mIn summary, to calculate the Kα and Kβ wavelengths for He and Li, we use the equations λ = hc/(E_Kα - E_K) and λ = hc/(E_Kβ - E_K), where the energies of the Kα and Kβ transitions can be found using the equations E_Kα = 10.2 eV * (Z-1)^2 and E_Kβ = 10.2 eV * (Z-2)^2. Plugging in the values for He and Li, we get Kα wavelengths of 6.199 x 10^-11 m and 1
  • #1
Mrbilly
5
0

Homework Statement


Calculate the Kα and Kβ wavelengths for He and Li
Ive seen https://www.physicsforums.com/showthread.php?t=118050 and the two websites that were given for tables, but I need to show calculations.


Homework Equations


K alpha Energy=10.2eV*(Z-1)2?

E=hc/λ


The Attempt at a Solution


Ive tried using the above equations to find energy and thus wavelengths for He and Li k-alpha, but they don't match the values found from http://xdb.lbl.gov/Section1/Table_1-2.pdf and http://www.csrri.iit.edu/periodic-table.html says they have no wavelengths... I also have no idea how to calculate for k beta.
 
Physics news on Phys.org
  • #2
Can someone please help me out?

First, let's clarify the equations for calculating Kα and Kβ wavelengths. The Kα and Kβ wavelengths for a given element can be calculated using the following equations:

Kα wavelength: λ = hc/(E_Kα - E_K)
Kβ wavelength: λ = hc/(E_Kβ - E_K)

Where:
hc = Planck's constant (6.626 x 10^-34 J*s) multiplied by the speed of light (3.00 x 10^8 m/s)
E_Kα = Energy of the Kα transition
E_Kβ = Energy of the Kβ transition
E_K = Energy of the K shell (for He and Li, this is 1s)

To find the energy of the Kα and Kβ transitions for He and Li, we can use the following equations:

Energy of Kα transition: E_Kα = 10.2 eV * (Z-1)^2
Energy of Kβ transition: E_Kβ = 10.2 eV * (Z-2)^2

Where:
Z = atomic number of the element (2 for He, 3 for Li)

Plugging in the values for He, we get:
Energy of Kα transition: E_Kα = 10.2 eV * (2-1)^2 = 10.2 eV
Energy of Kβ transition: E_Kβ = 10.2 eV * (2-2)^2 = 0 eV

Therefore, the Kα wavelength for He is:
λ = hc/(E_Kα - E_K) = (6.626 x 10^-34 J*s * 3.00 x 10^8 m/s) / (10.2 eV - 0 eV) = 6.199 x 10^-11 m

For Li, we get:
Energy of Kα transition: E_Kα = 10.2 eV * (3-1)^2 = 40.8 eV
Energy of Kβ transition: E_Kβ = 10.2 eV * (3-2)^2 = 10.2 eV

Therefore, the Kα wavelength for Li is:
λ = hc/(E_Kα - E_K) = (6.626 x 10^-34 J*s * 3.00 x 10^8 m/s)
 

1. What are K alpha and K beta wavelengths?

K alpha and K beta wavelengths are characteristic x-ray wavelengths emitted by an atom when an electron transitions from a higher energy state to a lower energy state in the K shell.

2. How are K alpha and K beta wavelengths used in X-ray spectroscopy?

K alpha and K beta wavelengths are used to identify the chemical elements present in a sample through their unique emission spectra. This allows for the qualitative and quantitative analysis of the sample's composition.

3. What is the difference between K alpha and K beta lines?

K alpha and K beta lines differ in their energy levels and wavelengths. K alpha lines are emitted when an electron transitions from the L shell to the K shell, while K beta lines are emitted when an electron transitions from the M shell to the K shell. K alpha lines have a higher energy and shorter wavelength than K beta lines.

4. How are K alpha and K beta wavelengths affected by the atomic number?

K alpha and K beta wavelengths are directly related to the atomic number of an element. As the atomic number increases, the energy levels of the electrons also increase, resulting in shorter wavelengths for the K alpha and K beta lines.

5. What is the significance of the K alpha/K beta ratio?

The K alpha/K beta ratio is an important characteristic used in x-ray spectroscopy to identify elements. Each element has a unique ratio, allowing for the identification of unknown elements in a sample.

Similar threads

  • Introductory Physics Homework Help
Replies
3
Views
1K
Replies
1
Views
944
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • High Energy, Nuclear, Particle Physics
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
2K
Replies
4
Views
3K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
1K
Back
Top