1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Light globe brightness change with voltage

  1. Oct 28, 2012 #1
    1. The problem statement, all variables and given/known data

    If a 6v incandescent globe is running at 6v with 0.6amps has a 0.909 resistor introduced into it's circuit which drops the voltage across it to 5.501v and 0.55amps how much does the brghtness change?

    3. The attempt at a solution

    5.501*0.55/6*0.6 original brightness. Is it as simple as this? Because I know globes are a non-ohmic conductor.
    Last edited: Oct 28, 2012
  2. jcsd
  3. Oct 28, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    There is enough information in the question to allow you to calculate if the resistance has changed.

    I believe your approach is correct (eg ratio of power) but perhaps add what other assumption you have to make about a bulbs brightness.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook