Which means of x-ray production involves projectile electrons knocking out inner shell electrons of tungsten?

• A. compton
• B. characteristic
• C. Bremsstrahlung
• D. photoelectric

Answer: (B)

The main idea is characteristic radiation. When high-energy projectile electrons collide with tungsten atoms, they can eject a tightly bound inner-shell (K-shell) electron, creating a vacancy. An electron from a higher shell then drops into that vacancy, and the energy difference between the two shells is emitted as a photon with a discrete, element-specific energy. That results in line spectra that are characteristic of tungsten. This mechanism requires the incident electron energy to exceed the inner-shell binding energy. In contrast, Bremsstrahlung produces a continuous spectrum from deceleration, Compton scattering involves photons scattering off electrons, and the photoelectric effect involves photon absorption by an atom rather than electron impact ejecting an inner-shell electron.