[Physics] How does the magnetic field get induced in car’s tire

electromagnetismelectrostaticseveryday-lifemagnetic fields

I was amazed to see how my car's tire started attracting the nuts and bolts, how in the world did it induce the magnetic field? Never heard of such phenomena!!!

Best Answer

Car tyres, which these days are almost always radials, are sometimes reinforced with steel. It may be possible that these have become magnetized due to impact in the Earth's field, although I find that unlikely unless you constantly drive in one direction.

Otherwise, maybe someone has run a magnet over your tyres?

Adding quotes from another paper on the subject

Magnetic fields emanate from radial tires due to the presence of reinforcing belts which are made of magnetized steel wire. When these tires spin, they generate alternating magnetic fields of extremely low frequency (ELF), usually below 20 Hz. The fundamental frequency of these fields is determined by tire rotation rate and has a sinusoidal waveform with a high harmonic content. The static field of radial tires can exceed 500 microT at the tread, and the tire-generated alternating fields can exceed 2.0 microT at seat level in the passenger compartment of vehicles.

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