Understanding Waves: Communication, Types, and the Electromagnetic Spectrum

1. Waves and Communication

Electromagnetic waves are transmitted through various communication systems, such as radio, telephone, or even our voice. A wave is a disturbance that travels through space without transferring material, but energy.

Features of Waves

• The time it takes for one complete oscillation is called the period.
• The number of oscillations per second is called frequency (f) and equals the inverse of the period: f = 1 / T. It is measured in s^-1, also known as Hertz (Hz).
• The distance between two peaks (the highest points of a wave) or two valleys (the lowest points of a wave) is the wavelength (λ). The longer the wavelength, the lower its frequency.
• The amplitude (A) is the maximum distance a particle displaced by the wave reaches from its equilibrium position. This is related to the energy transferred by the wave; a larger amplitude means more energy is transferred.

Types of Waves

Mechanical Waves

Mechanical or material waves require a material medium to propagate. Examples include water waves, sound waves, or waves traveling through a rope.

Electromagnetic Waves

These waves can propagate through a vacuum and also through certain materials.

The Electromagnetic Spectrum

The electromagnetic spectrum is the range of all types of electromagnetic radiation.

• At one end of the spectrum are the most energetic and dangerous radiations: X-rays and gamma rays, which have shorter wavelengths and higher frequencies.
• In the intermediate zone, radiation is associated with light, from infrared to ultraviolet, including the visible spectrum.
• At the other end are radio waves or radio frequencies, with long wavelengths and low frequencies, used by various wireless communication systems (including radio waves and microwaves). Each system uses a different band of the spectrum:

  Frequency Bands

  • Radio stations broadcast from 535 kHz to 108 MHz.
  • Television broadcasts between 50 and 850 MHz.
  • Mobile phones operate at frequencies from 824-894 MHz. Mobile phone antennas operate between 1800 and 2200 MHz, which are relatively high frequencies.
  • Remote controls for garages, cars, planes, and other equipment often operate using radio waves between 40 and 80 MHz.

2. Radio