Comparing Wavelengths of Red & Violet

The visible spectrum is associated with the colours red, orange, yellow, green, blue and violet.

No! The visible spectrum is just a small part of the electromagnetic spectrum our eyes are tuned to.

The relationship between wavelength and colour is that wavelength is a property of electromagnetic waves whilst human observers see different wavelengths as colours.

The unit used to measure the wavelengths of visible light is the nanometre.

Yes! The visible spectrum is composed of wavelengths between 390 to 700 nanometers and each wavelength is associated with a different colour.

A nanometre (nm) is a unit of length in the metric system, equal to one billionth of a metre (1 nm = 1 × 10⁻⁹ metres). It is commonly used to measure extremely small distances, particularly at the atomic and molecular scale.

• In the context of light and electromagnetic radiation, a nanometre is often used to describe wavelengths of visible light.
  The wavelength of visible light ranges from about 700 nm (red) to 400 nm (violet).
• Nanometres are also used to measure components like the thickness of materials, the size of particles in nanotechnology, and the spacing between atoms in a crystal lattice.

The electromagnetic spectrum includes electromagnetic waves with all possible wavelengths of electromagnetic radiation, ranging from low-energy radio waves through visible light to high-energy gamma rays.

• There are no precisely defined boundaries between the bands of electromagnetic radiation in the electromagnetic spectrum.
• The electromagnetic spectrum includes, in order of increasing frequency and decreasing wavelength: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays.
• Visible light is only a very small part of the electromagnetic spectrum.

A wave diagram is a graphic representation, using specific drawing rules and labels, that depicts variations in the characteristics of light waves. These characteristics include changes in wavelength, frequency, amplitude, speed of light and propagation direction.

• A wave diagram provides a visual representation of how a wave behaves when interacting with various media or objects.
• The purpose of a wave diagram is to illustrate optical phenomena, including reflection, refraction, dispersion, and diffraction.
• Wave diagrams can be useful in both theoretical and practical applications, such as understanding the basics of the physics of light or when designing complex optical systems.

Wavelength is the distance from any point on a wave to the corresponding point on the next wave. This measurement is taken along the middle line of the wave.

• While wavelength can be measured from any point on a wave, it is often simplest to measure from the peak of one wave to the peak of the next, or from the bottom of one trough to the bottom of the next, ensuring the measurement covers a whole wave cycle.
• The wavelength of an electromagnetic wave is usually given in metres.
• The wavelength of visible light is typically measured in nanometres, with 1,000,000,000 nanometres making up a metre.
• Each type of electromagnetic radiation – such as radio waves, visible light, and gamma waves – corresponds to a specific range of wavelengths on the electromagnetic spectrum.

Electromagnetic radiation is a type of energy more commonly simply called light. Detached from its source, it is transported by electromagnetic waves (or their quanta, photons) and propagates through space at the speed of light.

• Electromagnetic radiation (EM radiation or EMR) includes radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays.
• Man-made technologies that produce electromagnetic radiation include radio and TV transmitters, radar, MRI scanners, microwave ovens, computer screens, mobile phones, all types of lights and lamps, electric blankets, electric bar heaters, lasers and x-ray machines.
• At the quantum scale of electromagnetism, electromagnetic radiation is described in terms of photons rather than waves. Photons are elementary particles responsible for all electromagnetic phenomena.
• The term quantum refers to the smallest quantity into which something can be divided. A quantum of a thing is indivisible into smaller units so they have no sub-structure.  A photon is a quantum of electromagnetic radiation.
• A single photon with a wavelength corresponding with gamma rays might carry 100,000 times the energy of a single photon of visible light.