# Homework Help: Magnetic force on a circuit

1. Apr 24, 2014

### Saitama

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

(Ans: A,B,C,D)

2. Relevant equations

3. The attempt at a solution
The magnitude of force on the structure is given by

$$|I(\vec{AC}\times \vec{B})|=I|\vec{AC}||\vec{B}|\sin(\pi/4)$$
From the question, $I=2\,A$, $|\vec{AC}|=2\sqrt{2}\,m$ and $|\vec{B}|=2\,T$. Hence,
$$|F|=2\times 2\sqrt{2}\times 2 \times \frac{1}{\sqrt{2}}=8\,N$$
However, this is incorrect as per the answer key.

Any help is appreciated. Thanks!

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2. Apr 24, 2014

### dauto

What does the answer key say?

3. Apr 24, 2014

### Saitama

I already stated the answers below the image. The correct choices are A,B,C,D.

4. Apr 24, 2014

### dauto

The key says they are all correct? I agree with you. A seems to be off by a factor 21/2

5. Apr 24, 2014

### Saitama

Yes, all the options are correct. I already proved that B,C,D are correct, I was unsure about only the A option. Thanks dauto for the check! :)