TSA CBT Practice Test 2026 – The Complete All-in-One Guide for Exam Success!

The correct answer is that hard plastics and metals would be shown as red in an X-ray. This result occurs because X-ray machines use varying degrees of brightness or color to represent the density of the materials being scanned. Denser materials, such as hard plastics and metals, absorb more X-rays and appear in a contrasting color, often designated as red or another bright color in the imaging system.

In contrast, organic powders and liquids typically appear in shades that indicate they are less dense, such as lighter colors. Fabric, carton, and paper are also less dense than metals and hard plastics, which is why they would not register as red. Biological materials can vary in density, but they generally do not reflect the same density profile as metals and hard plastics, leading them to show different colors in the imaging context. Thus, when analyzing X-ray images, it's essential to understand how density influences the color representation of materials.