When an unmagnetized object, typically made of ferromagnetic material (like iron), approaches an electromagnet, the magnetic domains within the object begin to respond to the external magnetic field produced by the electromagnet. Here's what happens:
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Induction of Magnetic Field: The electromagnet generates a magnetic field when an electric current flows through its coils. This field extends into the surrounding space and can influence nearby magnetic materials.
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Alignment of Domains: The magnetic domains within the unmagnetized ferromagnetic object are initially oriented randomly, so their overall magnetic effect cancels out. However, as the object gets closer to the electromagnet, the magnetic field interacts with the magnetic domains in the object.
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Domain Reorientation: The presence of the external magnetic field causes the magnetic domains to become aligned with the field. This means that some domains will start to reorient themselves in the direction of the magnetic field, which leads to an increase in the object’s overall magnetization.
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Partial Magnetization: As more domains align with the magnetic field, the object becomes partially magnetized. The extent of this magnetization depends on the strength of the magnetic field and the properties of the material.
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Magnetization may become permanent: If the magnetic field is strong enough and the object has certain material properties (specific ferromagnetic materials), the alignment of the domains may become permanent even after the object is removed from the field. This phenomenon is known as hysteresis.
In summary, the approach of an electromagnet to an unmagnetized ferromagnetic object leads to the alignment of its magnetic domains with the externally applied magnetic field, resulting in the temporary or even permanent magnetization of the object.