What photon energy is produced by a tungsten anode when a K-shell vacancy is filled by an M-shell electron?

What photon energy is produced by a tungsten anode when a K-shell vacancy is filled by an M-shell electron?

• A. 72.5 keV
• B. 69.0 keV
• C. 66.5 keV
• D. 120 keV

Answer: (C)

A K-shell vacancy filled by an electron from the M shell produces a K-beta characteristic X-ray. Its energy equals the difference in binding energies between the K and M shells (E_K − E_M). For tungsten, this difference is about 66–67 keV, so the emitted photon is around 66.5 keV. Among the given options, 66.5 keV is the appropriate value for this transition. The other numbers don’t match this specific K to M transition: they either correspond to different transitions (like higher or lower shell changes) or to edge energies rather than the K–M transition energy for tungsten.

A K-shell vacancy filled by an electron from the M shell produces a K-beta characteristic X-ray. Its energy equals the difference in binding energies between the K and M shells (E_K − E_M). For tungsten, this difference is about 66–67 keV, so the emitted photon is around 66.5 keV. Among the given options, 66.5 keV is the appropriate value for this transition.

The other numbers don’t match this specific K to M transition: they either correspond to different transitions (like higher or lower shell changes) or to edge energies rather than the K–M transition energy for tungsten.