# Magnetic field and its energy?

1. Sep 28, 2007

### pivoxa15

1. The problem statement, all variables and given/known data
If a magnetic field has length 1m and strength 1T. What is its energy contained in it?

3. The attempt at a solution
I have no idea as I only know how to calculate energy from a volume basis.

2. Sep 29, 2007

### chaoseverlasting

$$F=\frac{-dU}{dx}$$, If you solve for U, you get your general expression and plug in the values there.

3. Sep 29, 2007

### Gokul43201

Staff Emeritus
This question looks nonsensical. Did you write it down exactly as it was given to you? Where is this from?

4. Sep 29, 2007

### pivoxa15

The question was about the magnetic prominence which is a magnetic loop. I just simplified the data but its about a magnetic loop and finding how much energy it can contain.