Electromagnetic Waves

They are waves which can travel through a vacuum.

Creation of Electromagnetic Waves

When a charged particle creates an oscillating electric field, an oscillating magnetic field is generated by the attracted positive particle. This all begins at the source of the wave. The vibrations in the fields then create a wave in which the two fields are perpendicular to each other. Because of this, electromagnetic waves move in a similar way to transverse mechanical waves.

Electromagnetic vs. Mechanical Waves

There are many ways that electromagnetic and mechanical waves contrast, such as:
  • Mechanical waves require a medium; electromagnetic ones can travel through a vacuum.
  • Rather than being categorized by the way they change the position of the particles within the medium like mechanical waves, electromagnetic waves are sorted by how high or low their wavelengths and frequencies are.

The Electromagnetic Spectrum

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Electromagnetic radiation, the type of energy released by waves, can have many different frequencies, energy levels, and wavelengths. The electromagnetic spectrum is the range of these characteristics which organizes different types of electromagnetic radiation. Along the illustration above, the names of each type of radiation are listed periodically. Waves with a longer wavelength are on the left, and waves with a shorter wavelength are on the right; this means that the waves of a higher frequency and energy level are on the right, and waves of a lower frequency and energy level are on the left. Below are both the types of radiation on the spectrum and the energy which is transported by electromagnetic waves.

Types of Electromagnetic Radiation

Visible Light

Visible light is what we use to see; objects such as light bulbs and lamps also emit it. Its wavelength is from from 4 x 10^-7 to 7 x 10^- m. Its frequency is from 4 x 10^14 to 7.5 x 10 ^14 Hz, and its energy is from 3 x 10^-19 to 5 x 10-19 J. This all makes visible light the middle of the spectrum.
Electromagnetic waves and the electromagnetic spectrum | Physics | Khan Academy
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This presentation was created by Isabelle deBruler.