How to determine the brightness of a light bulb

  1. In general, does more current/less resistence mean the brighter of the light bulb? How does voltage take into account in this case
  2. jcsd
  3. ranger

    ranger 1,684
    Gold Member

    Both the current and voltage contributes to the brightness. It just depends on the configuration. If an incandescent is 100% efficient (with it isnt btw), that means all power (V*I) would be used to produce visible light rather than 90% being wasted as heat.
  4. "Brightness" is a measure of power, so at constant voltage power is I^2R. If resistance is decreased and current is increased by an equal factor, the increase in current counts for more and the bulb will appear brighter
Know someone interested in this topic? Share a link to this question via email, Google+, Twitter, or Facebook

Have something to add?