# Homework Help: Circuit Problem with Wattages instead of Resistances

1. Apr 15, 2010

### aznshark4

1. The problem statement, all variables and given/known data
there is a 110-V battery serving as a voltage source, and the circuit goes like:

from the battery, there is a 100-Watt bulb connected, then the circuit branches into two parallel wires each with 100-Watt bulbs, then the wires rejoin and lead back to the battery, find everything you can.

2. Relevant equations
P=VI
R=V/I

3. The attempt at a solution
I don't even know where to begin, I tried finding the current but realized that I needed the Power too to solve, and I don't know how to get the power either.

2. Apr 15, 2010

### Staff: Mentor

Imagine a single 100W bulb connected directly to 110V battery. Can you calculate current?

3. Apr 15, 2010

### NeoDevin

Try to figure out the effective resistance of the circuit first.

4. Apr 15, 2010

### aznshark4

it's 3R/2 but i still don't know R

5. Apr 15, 2010

### NeoDevin

Consider a single light bulb on a simple circuit. That's what the 100W power rating is (generally) defined for.

6. Apr 15, 2010

### Staff: Mentor

As if I were reading my earlier post :grumpy:

7. Apr 15, 2010

### NeoDevin

Sometimes people need to be told more than once.