Why can cheap LED lights cause eye strain that old bulbs didn't?
Show answer & explanation
Answer: Flicker too fast to perceive
Color temperature varies widely — Partly true — color temperature changes the mood of a room (warm vs cool white), but it doesn't cause the eye strain and headaches people report. That points to something faster than the eye can see.
Flicker too fast to perceive ✓ — Correct! Cheap LEDs flicker at 100–120 Hz (twice the AC line frequency) because they use low-cost drivers. It's too fast to see consciously, but the eyes and brain still register it, causing eye strain and headaches for some people. Quality LEDs use better drivers — higher frequency or smoothed DC — to remove the flicker.
LEDs produce directional beams — Wrong. LEDs are directional, but a focused beam doesn't cause eye strain. The real culprit behind LED discomfort is high-frequency flicker from the power supply.
More Physics in Daily Life questions
- In a warm office that already reads 26 C, which change can make people feel cooler without lowering the thermostat?
- Why might 26 C feel acceptable in a breezy naturally ventilated summer building but too warm in a sealed winter office?
- On a warm humid day, why can the same 27 C room feel much worse once you start sweating?
- Why can moving air make a 27 C room feel cooler without changing the thermometer?
- Which hidden factor can make a desk beside a cold window feel chilly even when the thermostat across the room still reads 22 C?
- In the same 22 C room, why might someone who just climbed stairs feel warm while someone sitting in a T-shirt feels chilly?