Magnetism – Magnets and Magnetic Fields

Every magnet has two poles: North (N) and South (S). These are the regions where the magnetic force is strongest. The fundamental rule of magnetism is:

You cannot have a magnetic monopole—cutting a magnet in half creates two smaller magnets, each with its own N and S pole.

A magnetic field is the region around a magnet where magnetic forces act on other magnetic materials. We represent these fields using field lines:

• Field lines emerge from the North pole and enter the South pole
• Lines never cross each other
• Closer lines indicate a stronger field
• Lines form complete loops (continuing inside the magnet from S to N)

Magnetic field strength is measured in Tesla (T). Earth's magnetic field is about 50 µT, while a fridge magnet is about 5 mT.

Ferrous materials are attracted to magnets. These include iron, steel, nickel, and cobalt. These materials can become temporary magnets through induced magnetism when placed near a magnet.

Non-ferrous materials like copper, aluminum, brass, and gold are not attracted to magnets.

Earth behaves like a giant bar magnet with its magnetic south pole near the geographic North Pole. This field is generated by convection currents in Earth's liquid iron core.

A compass needle aligns with Earth's magnetic field, pointing towards magnetic north. Earth's magnetic field also protects us from harmful solar radiation by deflecting charged particles.