Module # 1 - Nature of Light Flashcards
Wavelength of the visible region
380nm-780nm
Wavelengths used in a clinical laboratory
Visible, UV, infrared
Wavelength
The distance between two consecutive peaks (or troughs) in the wave pattern expressed in nanometers (nm) Light with a short wavelength has a high energy. Light with a long wavelength has low energy.
Amplitude
The total wave height which relates to the intensity.
Frequency
The number of wave cycles passing a given point per second.
Velocity
The speed of light, depending upon the medium the light wave is travelling through.
Two properties of electromagnetic radiation
Travels in waves, interacts with matter as particles (photons.)
Polychromatic
Light consisting of all or a portion of the wavelengths of the spectrum.
Monochromatic
Light of one specific wavelength. The eye only recognizes light of one wavelength as an individual colour.
Reflection
The change in direction of a wave of light due to interaction with reflecting surfaces such as a mirror, water surface or shiny metals.
Refraction
As light passes from one medium to another, the change in medium density alters the velocity (e.g. when light passes from air to glass it slows down, when it goes from glass to air it speeds up.)
Diffraction
As light passes through a narrow slit or opening, it is bent or diffracted by the edges of the slit. For polychromatic light, the extent of diffraction varies with wavelength.
Interference
Occurs as a result of lightwaves interacting with each other. Light waves that are synchronized (peaks and troughs match) are described as being in phase. Light waves that are not synchronized are termed out of phase.
Polarization
Light that is orientated in multiple planes is termed unpolarized. Light that is oriented in one plane is termed polarized.
