Which of the following statements on the use of X-rays is incorrect? X-rays are used

Analysis of the Question

This question tests your knowledge of the practical applications of X-rays in medicine, industry, and security. We need to identify which of the listed options is not a valid use of X-rays.

Concept Explanation

X-rays are high-energy electromagnetic radiations with short wavelengths. Their properties include:

• High Penetrating Power: They can pass through soft tissues but are absorbed by denser materials like bones or metals.
• Ionizing Radiation: They can damage or destroy living cells, which is why they are used in radiotherapy.
• Fluorescence: They cause certain materials to glow.

Let's evaluate the options:

• Option A: X-rays are widely used in radiography to visualize bones and dense tissues because bones absorb more X-rays than soft tissue, creating a contrast on the film. This is correct.
• Option B: Because X-rays are ionizing, they can be used in controlled doses to kill cancerous cells (radiotherapy). This is correct.
• Option C: Fingerprint detection is typically done using optical scanners, powders, or chemical reagents (like ninhydrin) that react with the amino acids in sweat. X-rays are not used for this purpose. This is incorrect.
• Option D: In industrial radiography, X-rays are used to inspect metal castings and welds for internal cracks or air bubbles, as these flaws show up as variations in density. This is correct.

Step-by-Step Solution

1. Review the properties: X-rays are used for imaging (A), medical treatment (B), and industrial inspection (D).
2. Evaluate the outlier: Fingerprint detection relies on surface patterns and chemical residues, not the high-penetration imaging capabilities of X-rays.
3. Conclusion: Since the question asks for the incorrect statement, Option C is the right choice.

Exam Tip

When you see "Which of the following is incorrect/not true," always look for the option that describes a process involving a different part of the electromagnetic spectrum. For example, fingerprints are usually detected using visible light or chemical forensic methods, not ionizing radiation like X-rays.