Magnetism and Electromagnetism

Two ends of a magnet, where the magnetic force is strongest. One end is labeled North (N) and the other South (S).

Magnets with the same poles repel each other. Magnets with opposite poles attract each other.

A magnet that is always magnetic, always has poles, and does not require an outside force to be magnetic.

A material which is magnetic but does not have fixed poles in the absence of an outside magnetic field. These can be temporarily magnetized by being stroked with a permanent magnet.

The region around a magnet where the magnetic force can be detected, represented by magnetic field lines. Field lines point from North to South.

Small compasses used to map magnetic field lines by aligning themselves with the direction of the magnetic field.

The Earth's core (deep inside the Earth) generates a magnetic field, causing compasses to point towards it, near the geographic North Pole.

The Earth's South Magnetic Pole is located near the North Geographic Pole (and vice versa). This is because like poles repel, and the compass points to the Earth's South Magnetic Pole.

The flow of electric charge through a conductor. Current produces a magnetic field around the wire.

A rule that shows the direction of the magnetic field around a current-carrying wire. Imagine gripping the wire with your right hand, thumb pointing in the direction of current, fingers curl in the direction of the magnetic field lines.

The strength of the magnetic field produced by a current-carrying wire is directly proportional to the current flowing through it. A stronger current creates a stronger magnetic field.

The strength of the magnetic field produced by a current-carrying wire decreases as the distance from the wire increases.

A coil of wire that acts like a bar magnet when current flows through it. It creates a strong magnetic field because the individual fields of each loop add up.

An iron core inside a solenoid significantly increases the strength of the magnetic field, as magnetic field lines pass through iron more easily than air.

The force exerted on a current-carrying conductor placed in a magnetic field. This happens because the magnetic field of the wire interacts with the external magnetic field, creating a force.

A rule that relates the direction of the force experienced by a current-carrying conductor in a magnetic field to the directions of the magnetic field and the current.

The strength of the magnetic field at a particular point, measured in Tesla (T). It represents the density of magnetic field lines per unit area.

A device that converts electrical energy into mechanical energy (rotational motion). It consists of a coil of wire placed in a magnetic field and the coil rotates when current passes through it.

A device that converts mechanical energy (rotational motion) into electrical energy. It works by rotating a coil of wire in a magnetic field, inducing a current flowing in the coil.

The production of an electric current in a conductor due to a change in magnetic flux linked with the conductor. It occurs when there's relative motion between the conductor and the magnetic field.

A device that uses electromagnetic induction to transfer electrical energy between two coils (primary and secondary) using a changing magnetic field created by the primary coil.

A transformer that increases the voltage in the secondary coil compared to the primary coil. It has more turns on the secondary coil than on the primary coil.

A transformer that decreases the voltage in the secondary coil compared to the primary coil. It has fewer turns on the secondary coil than on the primary coil.

The formula that relates the number of turns on each coil of a transformer to the voltage across each coil.

Type of microphone that uses a movable coil of wire placed in a magnetic field. Sound waves cause the coil to move, inducing a current which is proportional to the sound signal.

Device that converts electrical energy into sound energy. It works by using an electromagnet to vibrate a cone, which produces sound waves.

Direct current (DC) flows in only one direction, while alternating current (AC) changes its direction periodically.

A type of generator that produces direct current (DC). It achieves this by using a split-ring commutator to reverse the current direction every half-rotation, ensuring the current always flows in the same direction.

A type of generator that produces alternating current (AC) by rotating a coil of wire in a magnetic field. The induced current changes direction every half-rotation, creating an alternating waveform.