Which feature glows orange under ultraviolet light on the $10 bill?

Which feature glows orange under ultraviolet light on the $10 bill?

• A. Watermark
• B. Color shifting ink
• C. Microprinting
• D. Security thread

Answer: (D)

Under ultraviolet light, features that fluoresce are used for quick authenticity checks. The security thread on the ten-dollar bill is designed to glow with UV exposure because it contains fluorescent material embedded in the note. This vertical thread emits orange light, making it easy to verify a genuine bill at a glance, which is why it’s the feature that glows orange under UV light. Other features work differently: a watermark appears when held up to light, not as a UV glow; microprinting is tiny text that’s best seen with magnification; and color-shifting ink changes hue with viewing angle, not with UV illumination. Understanding this helps you spot a genuine bill quickly by looking for the orange glow from the security thread.

Under ultraviolet light, features that fluoresce are used for quick authenticity checks. The security thread on the ten-dollar bill is designed to glow with UV exposure because it contains fluorescent material embedded in the note. This vertical thread emits orange light, making it easy to verify a genuine bill at a glance, which is why it’s the feature that glows orange under UV light. Other features work differently: a watermark appears when held up to light, not as a UV glow; microprinting is tiny text that’s best seen with magnification; and color-shifting ink changes hue with viewing angle, not with UV illumination. Understanding this helps you spot a genuine bill quickly by looking for the orange glow from the security thread.