If you install two new lightbulbs at the same time why will one of them burn out earlier? (like in car headlights)

Question

If you install two new lightbulbs at the same time why will one of them burn out earlier? (like in car headlights)

In: 1

Answer 1

Because no two physical things are exactly identical. There will be unavoidable differences in materials, manufacturing, environment (especially with your example of a car’s headlights), etc. These differences will result in difference in lifespan.