# What is the resistance of this device?

1. Apr 5, 2004

### Weather Freak

Hello, I am stumped on this question from my text book:

I tried by using this equation which I felt should work:

But it doesn't seem to get me the correct answer (which is 22 ohms). Any ideas? Thanks!

2. Apr 5, 2004

### ShawnD

$$P = \frac{V^2}{R}$$

$$R = \frac{V^2}{P}$$

$$R = \frac{1.5^2}{0.1}$$

$$R = 22.5 \Omega$$

Maybe the book is just wrong.

3. Apr 5, 2004

### Weather Freak

Thank you very much! Yeah... the 22 answer probably has something to do with sig figs.

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