What is the primary purpose of using an Alternate Light Source in forensic investigations?

• A. To disinfect surfaces
• B. To heat samples for analysis
• C. To visualize trace evidence such as hairs, fibers, fingerprints, and biological stains using various wavelengths
• D. To measure ambient light levels

Answer: (C)

Shining light at different wavelengths helps reveal trace evidence that is invisible under normal illumination by making substances fluoresce or contrast differently. An Alternate Light Source emits various wavelengths (UV, blue, green, etc.) and, with appropriate filters, causes hairs, fibers, fingerprints, and biological stains to stand out, guiding investigators to locate, document, and collect evidence. It’s about visualization of evidence through optical responses, not about disinfecting, heating samples, or measuring light levels. That’s why this option is the best fit.