# Why does the collapse of the magnetic field produce an electric field, and the reverse is that the collapse of the electric field produces a magnetic field?

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Why does the collapse of the magnetic field produce an electric field, and the reverse is that the collapse of the electric field produces a magnetic field?

In: Physics

https://en.m.wikipedia.org/wiki/Maxwell%27s_equations

It is due to the Maxwell equations. A change in strength in magnetic field results in a change in electric field, and vise versa.

It’s one of those bits in physics where you say “because that’s the way the universe works”.

Maxwell’s equations describe the phenomena, but they don’t say why it occurs.

It all has to do with the conservation of energy.

In reality, there is no such thing as magnetism. It’s the name we give to a moving electric field.

Consider a [Spring Mass System](https://media1.giphy.com/media/12EohK9HJIcsiQ/giphy.gif?cid=790b7611c7afc4c88023a0193f5839d31395a8fce875ee13&rid=giphy.gif).

The graph represents the height on the Y-axis, and the velocity on the X-axis. The circle it makes represents the conservation of energy. You’ll notice at the top and bottom, the height is maxed out (either at a high or a low) and the speed is zero – this represents maximum potential energy and minimum kinetic energy. You’ll notice at the far right or left, the speed is maxed out, and the height is zero (at the resting position) – this represents maximum kinetic energy and minimum potential energy. Note that the total energy is always constant and does not change, but how that energy is distributed is constantly changing.

Electric and magnetic fields work the same way. The electric field represents the potential energy, and the magnetic field represents kinetic energy. As light (electromagnetic waves) travel, they do so by oscillating the energy between potential energy (electric field) and kinetic energy (magnetic field).