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AC Circuits

by Mitchtwitchita
Tags: circuits
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Mitchtwitchita
#1
Jul8-10, 01:28 AM
P: 190
1. The problem statement, all variables and given/known data

Lightbulbs labeled 40 W, 60W, and 100 W are connected to a 120 V/60 Hz power line as shown in the diagram. What is the rate at which energy is dissipated in each bulb?



2. Relevant equations

Pr = (Vrms)^2/R

3. The attempt at a solution

I'm not exactly sure how to get this one started. Do I have to make some sort of equivalency lightbulb? Can somebody please point me in the right direction?
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rl.bhat
#2
Jul8-10, 02:08 AM
HW Helper
P: 4,433
Voltage across each branch is the same. Using the relevant equation find the resistance of each lamp.

Find the equivalent resistance of the circuit and the current in each branch.

Energy dissipated in each lamp is given by I^2*R.

Now proceed.
Mitchtwitchita
#3
Jul8-10, 03:40 AM
P: 190
Thanks a bunch rl.bhat!


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