8TH GRADE · MAGNETIC PHENOMENA
Magnetic field and electromagnet
Permanent magnets, current field, coil and application of electromagnets.
The entire theory of the lesson is collected here; you can read it without an account. In interactive mode, the same theory appears as cards, followed by questions. with checking the answer and task, and progress is saved.
Basic Concepts
Magnetic field
A form of matter that acts on magnets, moving charges, and current-carrying conductors.
Magnetic lines outside a permanent magnet are directed from the north pole to the south pole and do not intersect.
Magnetic field of current
Electric current creates a magnetic field around the conductor, the direction of which is related to the direction of the current.
In a coil, the fields of individual turns add up, forming a field similar to the field of a strip magnet.
Electromagnet
A current-carrying coil, often equipped with an iron core to enhance the magnetic field.
The strength of the electromagnet is controlled by current and the number of turns, and turning off the current allows you to quickly remove the main part of the field.
Physical quantities
Coil current
The strength of the current creating the magnetic field of the coil.
Unit: ampere ·
Related formulas
The same formulas in the reference, with symbols and units.
Tasks on the topic
Statements, answer options and the walkthrough.