Question

The maximum characteristic x-ray photon energy comes from the capture of a free electron into a K shell vacancy. What is this photon energy in keV for iridium assuming the free electron has no initial kinetic energy?

Answer 1

K-alpha emissions in x ray occurs when an electron jumps from second orbital called 2p orbital of second shell called L shell to innermost shell or 1 st shell called K shell .

And due to this transition a photon release whose energy will be equal to the energy difference of both the shell 2p & 1 p having principal quantum number 2 for 2p and 1 for 1 p.

E = - 13.6 Z^ 2/ n^2 electron volt (ev)

Z = atomic no. Here Iridium Z = 77

n = principal quantum number.

Enet = Ef - Ei

Ef = final energy here it is energy of 1 p orbital and n= 2

Ei = initial energy here it is energy of 2p orbital and n=1

Enet = -13. 6* (77)^ 2 /( 2 ) ^ 2 - (- 13. 6* (77)^ 2 / (1) ^ 2

E net = 60.48 kev