# Energy siored in an inductor

1. Apr 21, 2010

### FizixFreak

i know how can energy be stored in an object in a gravitational or electric field simply by working on the charge or mass agianst the respective field but how can energy be stored in a megnatic field i mean how would that be explained hypothatically ???

2. Apr 21, 2010

### marcusl

The fields that you mentioned are a form of stored energy, that is, it takes energy to create a gravitational or electric field in the first place. The same is true for a magnetic field. The energy stored in a magnetic field is

$$U=\frac{1}{2}\int\vec{H}\cdot\vec{B}dv$$

To drive home the point that the stored energy is the same as the work expended in creating the field, you'll often see this quantity called W (work) instead of U (energy).

3. Apr 24, 2010

### FizixFreak

so basically the work done to establish the megnatic field is stored in the inductor right but how is that energy utilized ??