Which interaction yields characteristic radiation when an inner-shell vacancy is filled?

Which interaction yields characteristic radiation when an inner-shell vacancy is filled?

• A. Coherent scattering
• B. Bremsstrahlung
• C. Characteristic
• D. Photoelectric absorption

Answer: (C)

Characteristic radiation is produced when an electron from a higher energy level drops into a vacancy in an inner shell. The energy released in this transition equals the difference in binding energies between those shells, giving a photon with a specific energy that is characteristic of the element. When an inner-shell vacancy is created, such as by ionization, electrons from above fill the gap and emit these element-specific photons. This distinguishes it from other interactions: coherent scattering involves elastic scattering with little or no energy change; bremsstrahlung is a continuous spectrum from deceleration of fast electrons; and photoelectric absorption absorbs the photon to eject a bound electron (the emission of characteristic radiation can follow later if another transition occurs, but the initial interaction is absorption, not emission of characteristic lines).

Characteristic radiation is produced when an electron from a higher energy level drops into a vacancy in an inner shell. The energy released in this transition equals the difference in binding energies between those shells, giving a photon with a specific energy that is characteristic of the element. When an inner-shell vacancy is created, such as by ionization, electrons from above fill the gap and emit these element-specific photons. This distinguishes it from other interactions: coherent scattering involves elastic scattering with little or no energy change; bremsstrahlung is a continuous spectrum from deceleration of fast electrons; and photoelectric absorption absorbs the photon to eject a bound electron (the emission of characteristic radiation can follow later if another transition occurs, but the initial interaction is absorption, not emission of characteristic lines).