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: Parallel Circuit

  1. Jun 28, 2010 #1
    1. The problem statement, all variables and given/known data

    A current I9 = 2 A flows through the 9 ohm resistor. At what rate does the battery deliver energy to the entire circuit?

    2. Relevant equations
    There are 3 resistors in the circuit, all wired in parallel. r1=15 ohms, r2=12 ohms, r3=9 ohms

    3. The attempt at a solution
  2. jcsd
  3. Jun 28, 2010 #2


    User Avatar
    Homework Helper

    What is the expression for the equivalent resistance of the parallel combination?

    What is the energy dissipation in the resistance?

    In the problem I9 and r3 is given. Find the applied voltage across the parallel combination.
  4. Jun 28, 2010 #3
    All I know is that resistance is 1/total=1/r1+1/r2+1/r3. I calculated 3.83 ohms
  5. Jun 28, 2010 #4


    User Avatar
    Homework Helper

    In parallel combination voltage across each branch of the resistance is the same.

    So V = I9*r3.

    Energy dissipation is W = V^2/r.
  6. Jun 28, 2010 #5
    Thank You. I was using the wrong equation for the last step
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook