What is the purpose of the metal core in an electromagnet? it is magnetized and induces a current in the solenoid to decrease the magnetic field strength. it is magnetized and induces a current in the solenoid to increase the magnetic field strength. it is magnetized by the field of the solenoid and increases the magnetic field strength. it is magnetized by the field of the solenoid and decreases the magnetic field strength

It is magnetized by the field of the solenoid and increases the magnetic field strength.

Explanation:

The metal core is usually made of iron in an electromagnet. When electric current passes through the wire wound about the core, the the metal core gets magnetized and concentrates the field lines; thus increases the magnetic field strength.

Hence, the purpose of the metal core in an electromagnet is that it increases the magnetic field strength on being magnetized by the field of solenoid.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia