Characteristic radiation is created when an electron knocks which shell out of orbit?

Characteristic radiation is created when an electron knocks which shell out of orbit?

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

Answer: (A)

When an incoming high-energy electron ionizes an atom, it can eject an inner-shell electron, leaving a vacancy. The atom then relaxes as electrons from higher shells drop into that vacancy, releasing photons with energies that are specific to that element—these are characteristic X-rays. The most prominent and well-known emissions come from a vacancy in the innermost shell, because removing that electron creates a K-shell vacancy. When an electron from a higher shell fills that K-shell vacancy, the emitted X-ray has a characteristic energy for the element, producing the characteristic radiation. If a vacancy occurred in a higher shell, you’d get lines from transitions into that shell (L-series, M-series, etc.), but the standard concept of characteristic radiation centers on the K-shell vacancy.

When an incoming high-energy electron ionizes an atom, it can eject an inner-shell electron, leaving a vacancy. The atom then relaxes as electrons from higher shells drop into that vacancy, releasing photons with energies that are specific to that element—these are characteristic X-rays. The most prominent and well-known emissions come from a vacancy in the innermost shell, because removing that electron creates a K-shell vacancy. When an electron from a higher shell fills that K-shell vacancy, the emitted X-ray has a characteristic energy for the element, producing the characteristic radiation. If a vacancy occurred in a higher shell, you’d get lines from transitions into that shell (L-series, M-series, etc.), but the standard concept of characteristic radiation centers on the K-shell vacancy.