[Circuits] Calculating the power absorbed by a resistor

[ainster31]

Homework Statement

Homework Equations

The Attempt at a Solution

Attached to this post.

I have calculated the power absorbed for the 6S and 5S resistors but not the 3S resistor.

 

[gneill]

Homework Statement

Homework Equations

The Attempt at a Solution

Attached to this post.

I have calculated the power absorbed for the 6S and 5S resistors but not the 3S resistor.

Your values look okay for the 6S and 5S resistors. Why didn't you calculate the power absorbed by the 3S resistor?

 

[ainster31]

Your values look okay for the 6S and 5S resistors. Why didn't you calculate the power absorbed by the 3S resistor?

Here is my attempt for the 3S resistor:

$$R=\frac { V }{ I } \\ \frac { 1 }{ 3 } =\frac { V }{ 6 } \\ V=2\quad V\\ \\ P=VI\\ P=2\cdot 16\\ P=32\quad W$$

 

[gneill]

Here is my attempt for the 3S resistor:

$$R=\frac { V }{ I } \\ \frac { 1 }{ 3 } =\frac { V }{ 6 } \\ V=2\quad V\\ \\ P=VI\\ P=2\cdot 16\\ P=32\quad W$$

Where did you get 16 A from for your P = VI calculation? You used I = 6 A in the second line.

Note that while power is indeed given by P = VI, for a resistor it's also given by V²/R and I²R, so you can avoid some steps if you already have either V or I.

 

[ainster31]

So P=12W?

 

[gneill]

So P=12W?

Is that a guess or a conclusion?

 

[ainster31]

Conclusion.

I used 16 A by accident. Not sure where I got the 1 from.

 

[gneill]

Okay, so it looks like you're done

 

[HugeLaser]

You got right.