Brehmsstrahlung X-rays have a ____ of energies.

• A. Range
• B. Fixed
• C. Variable
• D. Spectrum

Answer: (A)

Brehmsstrahlung X-rays arise when fast electrons are slowed in a target, and this deceleration can emit photons with many different energies. That creates a continuous distribution of energies—from near zero up to a maximum energy set by the incident electron energy. Because there isn’t a single energy but a spread, it’s described as a range of energies. The other terms don’t capture that spread as effectively: a fixed energy would mean only one energy, and while the emission is indeed a spectrum, the prompt focuses on the idea of a spread or range of energies present. The maximum energy is determined by the electron beam, so the range extends up to that limit.