Magnets and magnetic fields  - Magnetism

Magnets and magnetic fields 

Lessons

Notes:

In this lesson, we will learn:

  • Magnets and Magnetic Fields
  • Erath’s Magnetic Filed
  • Uniform Magnetic Field

Notes:

  • Magnets attract objects made of iron such as paper clips and nails
  • Any magnet (bar magnet or horseshoe magnet) has two ends or faces, called “poles”, the strongest magnetic effect.
  • Compass is used for navigation; the needle of the compass is simply a bar magnet which is supported at its center of gravity to rotate freely.
  • The pole that points the geographic north is called the "north pole" and another pole which points towards the geographic south is called the "south pole".
  • Similar poles attract, opposite poles repel.


  • Magnets and Magnetic Fields

  • If you split a magnet, you will not get isolated north and south poles; instead, two new magnets are produced, each with a north and a south pole.
  • Ferromagnetic Materials: a type of material that shows strong magnetic effect such as, cobalt, nickel, gadolinium, and some of their oxides and alloys.
  • Magnetic Filed: the region around the magnets and it represented by magnetic field lines such as;
    1. the direction of the magnetic field is tangent to a field line at any point
    2. the number of lines per unit area is proportional to the strength of the magnetic field.
  • The direction of the magnetic field at a given point: it is defined as the direction that the north pole of a compass needle would point if placed at that point. The N pole of a nearby compass needle points away from the north pole of the magnet and points towards the south pole of the magnet.


  • Magnets and Magnetic Fields

  • Magnetic field lines form closed loops, unlike electric field lines.

    Erath’s Magnetic Filed
  • The Earth acts like a huge magnet; but its magnetic poles are not at the geographic poles, which are on the Earth rotational axis.
  • Since the north pole (N) of the compass needle points north, the Earth's magnetic pole which is in the geographic north is magnetically a south pole.


  • Magnets and Magnetic Fields

Uniform Magnetic Field
  • The simplest magnetic field is one that is uniform, it does not change in magnitude or direction.
  • The magnetic field between two poles of a magnet is nearly uniform, except at the edges.

  • Magnets and Magnetic Fields
  • Intro Lesson
Teacher pug

Magnets and magnetic fields 

Don't just watch, practice makes perfect.

We have over NaN practice questions in Physics for you to master.