A photoelectric sensor might use which type of light to prevent actuating too easily?

• A. Infrared Light
• B. Ultraviolet Light
• C. Visible Light
• D. X-Rays

Answer: (A)

Infrared light is used because it lets the sensor distinguish its own emitted signal from ambient lighting. IR LEDs and receivers are designed to work at a wavelength that isn’t part of the visible light people see, and the system can be tuned to respond only to that specific infrared signal, often by modulating the beam or using filters. This reduces false triggers from ordinary room or sunlight, making the sensor less sensitive to unwanted ambient light. Visible light would be easily disturbed by ambient illumination, ultraviolet poses safety and reliability issues, and X-rays are impractical for everyday sensing. Infrared thus provides reliable detection with fewer false actuations.