What is an EMP

A.� An EMP, or electro magnetic pulse, is the electromagnetic radiation from a nuclear explosion.

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When a nuclear bomb explodes gamma rays are released which collide with air molecules producing something called Compton's electrons. The Compton electrons interact with the earth's magnetic field, resulting in a huge electromagnetic pulse, or EMP. The EMP moves with the speed of light, effecting everything in its path.

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The EMP causes damaging current and voltage surges in electronic equipment

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Q.� How does EMP affect electrical equipment

A.� Modern electronic equipment is very sensitive to such strong electromagnetic fields and can become inoperable after experiencing EMP.

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Q.� Is it possible to protect electrical equipment against EMP

A.� There are some simple precautionary measures you can take. As long as your equipment isn't turned on or connected to the power supply when EMP strikes it won't be affected. But this assumes that you won't be using your equipment when EMP strikes: not something you can guarantee.

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Alternatively stick to using battery operated equipment and keep it around 2 metres away from any other metal object.

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Or you could use a Faraday box.

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Q.� What's a Faraday box

A.� It's just a metal box that soaks up EMP. As long as any equipment placed inside the box is insulated from the box's surface it wont be affected by EMP.

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You can make a Faraday box using an old cake tin with cardboard or waded paper for insulation.

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Q.� Should I be worried about a nuclear explosion and EMP

A.� To produce widespread EMP a nuclear explosion needs to be big and high, ideally from space, from where it could travel all over the earth. Any EMP effects from a nuclear explosion at ground level would be very localised.

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Q.� When were the dangers of EMP first noted

A.� By Enrico Fermi a physicist and member of the team based at Los Alamos In New Mexico, USA, that developed the first nuclear bomb.

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by Lisa Cardy