Electric & magnetic fields

Electromagnetic radiation, electric & magnetic fields

Electric and magnetic fields are fundamental forces responsible for generating and transmitting electromagnetic radiation, including light. Additionally, these fields govern the behaviour and interactions of electromagnetic radiation with the materials and substances they encounter.

• A change in an electric field induces a change in the magnetic field.
• A change in a magnetic field induces a change in the electric field.
• An electromagnetic wave is the result of the interaction between an electric field and a magnetic field.
• An electromagnetic wave travelling at the speed of light in a vacuum is produced when either the voltage (charge) of an electric field changes or when the amperage (current)
  in a conductor changes.
• When changes in electric and magnetic fields result in electromagnetic waves, they produce synchronized oscillations that travel at right angles to each other.
• The velocity at which electromagnetic waves propagate in a vacuum is the speed of light which is 299,792 kilometres per second.
• Once an electromagnetic wave radiates outward, it remains unaffected by an external electric or magnetic field.
• This is because electromagnetic waves are massless particles that travel at the speed of light.But here are exceptions to this rule:
  • If an electromagnetic wave passes through an immensely strong magnetic field, it may experience slight deflection.
    Another exception is the deflection of electromagnetic waves by gravitational fields. However, gravitational deflection of light only takes place in the presence of objects like galaxies and black holes.
• An electromagnetic wave does not need a medium to propagate through:
  • The fact that electromagnetic waves can propagate independently of matter is related to the nature of photons.
  • Photons are the elementary particles that constitute electromagnetic radiation meaning that electromagnetic radiation can be viewed as a stream of photons.
  • Photons are pure energy packets and are not composed of matter. As massless particles, they are not influenced by physical mediums or obstructions. They move through space freely at the speed of light, regardless of whether there is matter or a vacuum.
  • It’s important to note however that while electromagnetic waves can travel through a vacuum, they can also interact with and be affected by matter when they pass through different materials. This interaction with matter is the basis for various applications in optics, communications, and imaging, where electromagnetic waves interact with substances like glass, metals, or biological tissues.

Electromagnetic induction, electric & magnetic fields

• In the most simple terms, electromagnetic induction is a way of “creating electricity” in a wire by moving a magnet near it or changing the magnetic field around it.
• Electromagnetic induction is a phenomenon where a changing magnetic field induces an electric current in a conductor, such as a wire. Similarly, a changing electric field can induce a magnetic field.
• The mutual influence of electric and magnetic fields is at the core of electromagnetic induction and is used in technologies like generators, transformers, and even wireless charging.