Electromagnetic Waves

Section: Electromagnetic Waves

  • Electromagnetic (EM) waves are waves that can travel through space or matter, consisting of oscillating electric and magnetic fields.

  • These waves have diverse uses, determined by their different wavelengths and frequencies. Examples include radio waves for broadcasting, infrared for heat sensors, ultraviolet for tanning and sterilization, and X-rays for medical imaging.

  • They travel at a speed of 3x10^8 metres per second (speed of light) in a vacuum.

  • EM waves are categorized in the electromagnetic spectrum from low to high frequency (or high to low wavelength): Radio Waves, Microwaves, Infrared, Visible Light, Ultraviolet, X-rays, and Gamma Rays.

  • Radio waves have the longest wavelength, lowest frequency and energy, while Gamma rays have shortest wavelength, highest frequency, and energy.

  • All electromagnetic waves, regardless of types, transmit energy.

  • Visibly detected light consists of different mixtures of colors, each having a specific wavelength and frequency. Red light has the highest wavelength (and lowest frequency), Violet the shortest wavelength (and highest frequency).

  • Refraction is the change in direction or speed of EM waves as they pass from one medium to another (like air to water or glass), depending on wavelength, leading to phenomena like rainbow or dispersion.

  • Reflection occurs when EM waves bounce off a surface. The angle of incidence equals the angle of reflection.

  • Absorption happens when objects take in EM wave energy and convert it to other forms, like heat, causing them to warm.

  • Transmission is when EM waves pass through a substance without being absorbed.

  • Attenuation describes the decrease in energy or amplitude of EM waves as they travel through a medium.

It is crucial to understand the properties and behaviours of electromagnetic waves as it is an essential part of scientific knowledge. With mastery of this topic, you can better comprehend the everyday uses and implications of different types of electromagnetic waves.