Which Element Produces Lower Energy Ka X-rays in an Experiment?

[jije1112]

In an experiment one observes the characteristic Ka X-rays of two elements at energies of 6.930 and 7.478 eV. The higher energy line is due to Ni. What element is responsible for the lower energy line?

 

[mfb]

Is this homework? Edit: I moved it to the homework section.

Simply typing the energy into google gave a result within 10 seconds, faster than typing the question here.

 

[jije1112]

Is this homework?

Simply typing the energy into google gave a result within 10 seconds, faster than typing the question here.

I have to use formula to find it

 

[mfb]

Then you should look up that formula and use it.