How to Calculate Battery Voltage from Resistor Power Dissipation?

[crh]

Homework Statement

In the circuit shown, the 33-ohm resistor dissipates 0.50 W. What is the battery voltage?

http://phga.pearsoncmg.com/phga2/web/Giancoli6e/Public_Html/Chapter19/Aadxevw0.gif

Homework Equations

I am pretty sure that I use the equation V=IR, but I am not for sure how to go about using the 0.50W in the equation. At first I thought that I used P=IV for electric power, but I am just confused.

The Attempt at a Solution

I don't even know what equation to exactly use because the watts are throwing me off.

 

[LowlyPion]

Homework Statement

In the circuit shown, the 33-ohm resistor dissipates 0.50 W. What is the battery voltage?

http://phga.pearsoncmg.com/phga2/web/Giancoli6e/Public_Html/Chapter19/Aadxevw0.gif

Homework Equations

I am pretty sure that I use the equation V=IR, but I am not for sure how to go about using the 0.50W in the equation. At first I thought that I used P=IV for electric power, but I am just confused.

The Attempt at a Solution

I don't even know what equation to exactly use because the watts are throwing me off.

You should know from Watts = V*I and V= I*R that Watts = I²R
Watts is your equation for P = Power.

So knowing the watts of a resistor let's you figure out the current.

Knowing the current and figuring the equivalent resistance for the 3 resistors through the V=I*R tells you the voltage of the supply.

 

[crh]

thank you, I figured it out with your help.

 

[LowlyPion]

thank you, I figured it out with your help.

Good luck then.