Curent and ohm's law-potential difference

[smoics]

curent and ohm's law--potential difference

Homework Statement

What is the potential difference across the 10 ohm resistor in the figure ?
What is the potential difference across the 20 ohm resistor in the figure?
The two resistors are in parallel and there is a battery that is 15 V.

Homework Equations

V=IR

The Attempt at a Solution

I think it should be relatively straightfoward, but I can't figure out how to solve for I so that I can solve for V.

 

[gneill]

What is the potential difference across the 10 ohm resistor in the figure ?
What is the potential difference across the 20 ohm resistor in the figure?
The two resistors are in parallel and there is a battery that is 15 V.

Do you mean that all three components are in parallel (the battery in parallel with both resistors)? If so, how can the potential difference be anything other than what the battery produces? An ideal voltage source produces any amount of current required to maintain its potential difference.

 

[smoics]

Oops--yes, they are in parallel. I tried using the battery voltage (15 V), but it says that answer is incorrect.

 

[smoics]

Or would the one resistor be in series since it's along a different line (horizontal vs. vertical)? That isn't how they draw the examples of series vs. parallel, but I'm thinking there's one of each in this circuit.

 

[gneill]

If that diagram is your circuit then all three components are in series. There are none in parallel.

Series versus parallel does not depend upon whether the components are drawn vertically or horizontally. It is strictly a matter of how their terminal leads are interconnected.

Two components in series means that one lead from each component is connected together with NO OTHER component sharing that connection. The other leads of the components go to different nodes in the circuit.

Two components in parallel mean that both leads from both component share common connections (they are pairwise connected).

Since you circuit show a series connection, you should work out what the current will be in the circuit. To do that, first determine the total resistance for the series connected pair.

 

[smoics]

Oh...use the total R and voltage to solve for current and then use the equation I had posted above. Got it, thanks!