Visible light

Definition

Visible light is the portion of the electromagnetic spectrum that is detectable by the human eye, ranging from approximately 400 to 700 nanometers in wavelength. It plays a crucial role in microscopy and other techniques used to observe microorganisms.

5 Must Know Facts For Your Next Test

1. Visible light consists of different colors, each corresponding to a specific wavelength range; for example, blue light has shorter wavelengths (about 450 nm) while red light has longer wavelengths (about 650 nm).
2. In microscopy, visible light is often used with various staining techniques to enhance the contrast of microscopic specimens.
3. The resolving power of optical microscopes is limited by the wavelength of visible light, which means finer details smaller than about 200 nm cannot be resolved.
4. Visible light can be manipulated using lenses and mirrors to magnify images of small objects like bacteria and cells.
5. Fluorescence microscopy uses specific wavelengths within the visible light spectrum to excite fluorescent dyes attached to specimens, allowing them to emit visible light for visualization.

Review Questions

• What wavelength range does visible light cover?
• How does visible light contribute to enhancing contrast in microscopy?
• Why is the resolving power of optical microscopes limited by visible light?

Related terms

Electromagnetic Spectrum:

The range of all types of electromagnetic radiation, including visible light.

Fluorescence Microscopy:

A technique that uses fluorescence instead of or along with reflection and absorption to study properties of organic or inorganic substances.

Wavelength:

The distance between consecutive peaks or troughs in a wave, commonly measured in nanometers for visible light.