Magnetism | Physics for GCSE/IGCSE - Year 11 PDF Download

Magnetism

• The ends of a magnet are referred to as poles.
• Magnets possess two poles: a north pole and a south pole.

• Magnets are objects that exhibit attraction and repulsion.
• Similar poles repel each other. For instance, a north pole repels another north pole, and a south pole repels another south pole.
• Unlike poles attract each other. For example, a north pole is attracted to a south pole.
• When two magnets are close, a force acts between them.

• Magnetic materials:
  • Experience a force in a magnetic field.
  • Are attracted to a magnet when not magnetized.
  • Can be magnetized to become a magnet.
• Only a magnet can repel another magnet, serving as a useful test for magnetism.
• Non-magnetic materials do not respond to magnetic fields by experiencing a force.

Uses of Magnets

Uses of Permanent Magnets

• Permanent magnets are commonly crafted from steel, although exceptions exist.
  • These magnets possess a lasting magnetic quality.
    
• Permanent magnets serve various purposes, such as:
  • Compasses: Utilized for navigation over centuries due to their consistent alignment with the Earth's magnetic north.
  • School lab experiments: Employed in educational settings to illustrate magnetic principles.
  • Toys: Magnetized components in toy trains and trucks that connect carriages to the engine or cab.
  • Fridge magnets: Constructed from flexible magnetic material or by affixing a magnet to an object's back.

Uses of Electromagnets

• Electromagnets operate by using electricity to induce magnetism in a current-carrying wire.
• One key advantage of electromagnets is their ability to be magnetized or demagnetized instantly with a switch.
• They are easily turned on and off, providing flexibility in their magnetic properties.
• Soft iron is typically employed in electromagnets due to its capability to become a temporary magnet.

• Electromagnets have many uses including
  • MRI Scanners: In medical facilities, MRI scanners are large machines that utilize strong electromagnets to create detailed images of the body's organs.
  • Speakers and Earphones: Devices like phones and laptops employ electromagnets in their loudspeakers, microphones, and earphones to transmit and receive sound waves effectively.
  • Recycling: Steel, being a magnetic material, can be segregated from other substances through electromagnets, aiding in its reuse and minimizing the need for new steel production.
  • Mag-Lev Trains: Mag-Lev trains operate by utilizing large electromagnets to hover above the tracks, reducing friction and enabling speeds up to approximately 400 miles per hour.