Please help me with this one out.
The earth's magnetic field, like any magnetic field, stores energy. The maximum strength of the earth's field is about 7.0 x 10-5 T. Find the maximum magnetic energy stored in the space above a city if the space occupies an area of 7.5 x 106 m2 and has a height of 2100 m.
The earth's magnetic field, like any magnetic field, stores energy. The maximum strength of the earth's field is about 7.0 x 10-5 T. Find the maximum magnetic energy stored in the space above a city if the space occupies an area of 7.5 x 106 m2 and has a height of 2100 m.
-
The energy density (energy per volume) u of a magnetic field is
u = B² / (2 µ_0)
µ_0 is a constant, and you have B, so you can find the energy density of the field per volume. Multiplying by the volume above the city will give you the total energy.
****************
As a matter of interest, SmartAZ, how can something be a philosophical concept except in nuclear physics? And saying energy is defined as a frequency doesn't make sense—the dimensions aren't the same.
u = B² / (2 µ_0)
µ_0 is a constant, and you have B, so you can find the energy density of the field per volume. Multiplying by the volume above the city will give you the total energy.
****************
As a matter of interest, SmartAZ, how can something be a philosophical concept except in nuclear physics? And saying energy is defined as a frequency doesn't make sense—the dimensions aren't the same.
-
You're welcome. I'm glad to help.
Report Abuse
-
Energy is not a physical unit*, it is a philosophical concept. Except in nuclear physics where it is defined to be a frequency of light. Your question is wonky.
* Energy is sometimes defined as capacity to do work. But work is defined as disordering of energy. So energy is capacity to do disordering of energy, a circular definition.
* Energy is sometimes defined as capacity to do work. But work is defined as disordering of energy. So energy is capacity to do disordering of energy, a circular definition.