Magnetism and Electromagnetics

What materials can magnets attract?

Magnets can attract iron, steel, nickel, and cobalt.

What are the two poles of a magnet?

North pole and South pole.

What happens when like poles of a magnet are brought together?

Like poles repel each other.

What is the Law of Magnetism?

Unlike poles attract, and like poles repel.

What do magnetic fields represent?

The region around a magnet where a magnetic force is exerted.

What do magnetic field lines indicate?

The direction of the force on another north pole at that point.

How does the strength of a magnetic field change with distance from the magnet?

The strength weakens as the distance increases.

What tool can be used to plot magnetic fields?

A plotting compass.

What is a permanent magnet?

A magnet that creates its own magnetic field without needing an external source.

What is an induced magnet?

A magnet that becomes magnetic when placed in a magnetic field.

How can magnetic materials be magnetized?

By stroking with a magnet or leaving it near a magnet.

What shape does the magnetic field around a current-carrying wire take?

Circular magnetic field.

What does the Corkscrew Rule describe?

It helps determine the direction of the magnetic field based on current direction.

What defines a solenoid?

A coil of insulated wire that produces a magnetic field.

How can the strength of a solenoid's magnetic field be increased?

By increasing current, number of turns, or adding an iron core.

What happens to the magnetic field inside a solenoid compared to a bar magnet?

It is stronger and more uniform.

What is an electromagnet?

A solenoid with an iron core that becomes magnetized when current flows.

What is one advantage of electromagnets?

They can be turned on and off by controlling the current.

What is the Motor Effect?

The phenomenon where a current-carrying wire experiences a force in a magnetic field.

How can the strength of the force on the wire be increased?

By increasing magnetic flux density, current, or the length of the conductor.

What does Fleming's Left-Hand Rule help determine?

The direction of the force, magnetic field, and current in a wire.

What is induced potential difference?

A potential difference induced when a conductor moves relative to a magnetic field.

What is the purpose of a generator?

To generate electricity through electromagnetic induction.

What is the difference between an AC generator and a DC generator?

AC generators produce alternating current, while DC generators produce direct current.

How do microphones utilize the generator effect?

They convert sound waves into electrical signals by inducing potential difference.

What are the two types of transformers?

Step-up transformers and Step-down transformers.

What does a step-up transformer do?

Increases voltage and decreases current.

What is the National Grid?

A network of cables and transformers that distributes electricity.

Why is electricity transmitted at high voltages in the National Grid?

To reduce energy loss due to heating in the cables.

What is the transformer equation?

Vr/Vs = Nr/Ns, where V = voltage and N = number of turns.

What type of current flows through a solenoid in an electromagnet?

Direct current (DC) to create a magnetic field.

What is the shape of magnetic fields around a solenoid?

Similar to that of a bar magnet.

What induces current in a generator as the coil rotates?

Cutting through magnetic field lines.