"Braking radiation" refers to which phenomenon?

• A. Bremsstrahlung Radiation
• B. Central Ray
• C. Density
• D. Contrast

Answer: (A)

Braking radiation describes the process that happens when a fast electron is slowed down or deflected by the electric field of a nucleus, causing the electron’s lost energy to be emitted as photons in the X-ray range. This emission is the Bremsstrahlung radiation—the name literally coming from the braking motion of the electron. So the phenomenon referred to by braking radiation is Bremsstrahlung Radiation.

The other terms don’t fit: the central ray is just the direction of the X-ray beam, not a production process; density and contrast are image-formation properties, describing how dark or how distinguishable structures appear on the radiograph rather than how X-rays are produced.