Be window function:

• A. Increases filtration.
• B. Rotates the anode.
• C. Allows X-rays to exit with minimal attenuation while maintaining vacuum; Be has a low atomic number, reducing absorption of low-energy photons and improving beam quality.
• D. Provides shielding.

Answer: (C)

The window is there to let X-rays escape from the tube while keeping the internal vacuum intact. The beryllium window accomplishes this because it’s thin yet strong enough to withstand the pressure difference, and its low atomic number means X-rays aren’t absorbed much as they pass through. This minimizes attenuation of the beam, especially for the lower-energy photons, so the emitted X-ray beam remains of good quality and intensity.

If the window were made from a heavier, higher‑Z material, it would absorb more of the low-energy photons, softening and weakening the beam and reducing image quality. The window’s job is not to increase filtration by design, nor to rotate the anode, nor to provide shielding; these functions are handled by other components or materials in the system.