Homework Help: Help finding battery voltage.

1. Sep 17, 2008

crh

1. The problem statement, all variables and given/known data

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

2. Relevant 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.

3. The attempt at a solution

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

Last edited by a moderator: Apr 23, 2017
2. Sep 17, 2008

LowlyPion

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 lets 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.

Last edited by a moderator: Apr 23, 2017
3. Sep 17, 2008

crh

thank you, I figured it out with your help.

4. Sep 17, 2008

LowlyPion

Good luck then.