Characteristic x-rays are more likely to be produced when the projectile electron interacts with a bound electron in which shell?

Characteristic x-rays are more likely to be produced when the projectile electron interacts with a bound electron in which shell?

• A. M-shell
• B. K-shell
• C. N-shell
• D. L-shell

Answer: (B)

When a high-energy projectile knocks out a bound electron, the vacancy that forms is filled by an electron from a higher shell, and a photon with energy equal to the difference between those shells is emitted. The innermost shell, called the K-shell, has the highest binding energy, so a vacancy there produces the most energetic and distinctive X-ray lines (the K-series) that clearly identify the element. If the interaction involves outer shells, the emitted X-rays would be of lower energy and less characteristic. Thus, a bound-electron interaction in the K-shell is the most likely way to produce characteristic X-rays.

When a high-energy projectile knocks out a bound electron, the vacancy that forms is filled by an electron from a higher shell, and a photon with energy equal to the difference between those shells is emitted. The innermost shell, called the K-shell, has the highest binding energy, so a vacancy there produces the most energetic and distinctive X-ray lines (the K-series) that clearly identify the element. If the interaction involves outer shells, the emitted X-rays would be of lower energy and less characteristic. Thus, a bound-electron interaction in the K-shell is the most likely way to produce characteristic X-rays.