Modern bulbs for lighting are rated in

• A. Wattage
• B. Lux
• C. Color temperature
• D. Lumens

Answer: (D)

Brightness is about how much light a bulb emits, and that amount is measured in lumens. In modern lighting, wattage isn’t a reliable indicator of brightness because technologies like LEDs produce a lot more light per watt than older bulbs. Lux, while related, measures the light that actually reaches a surface (illuminance) and depends on distance and area, so it isn’t a rating you’d use to compare bulbs themselves. Color temperature tells you whether the light looks warm or cool (measured in kelvin), not how bright it is. So the rating that directly tells you the bulb’s brightness is lumens.