2.4 - Optics Flashcards
What is light?
A form of electromagnetic radiation
What is visible light measured in?
nanometres (Nm) or Angstrom (A)
What are the wavelengths of Ultraviolet light?
less than 4,000 A
What are the wavelengths of Infrared light?
More than 7,000A
What is the speed of light?
3x10^8 m/sec
What is the formula for the speed of electromagnetic radiation (c)?
c = f x lamda
frequency x wavelength
What is the law of reflection?
The angle of incidence = the angle of reflection
What happens to refraction at 90 degrees?
There is no refraction
What happens to light wave-fronts when they refract?
They change direction
What is the equation for the focal length of a concave mirror?
f = 1/2 x R (radius of curvature)
What happens to an image in a concave mirror?
(Magnifying bathroom mirror)
What happens to an image in a convex mirror?
Diminished image and fit more detail in (car rear-view mirror)
What are the three parts to a fibre optic data link?
Transmitter, receiver and optical fibre.
What are the two basic types of fibres?
Multimode and single-mode
What is the cladding layer of an optical fibre?
A dielectric material reducing the loss of light into surrounding air, adds mechanical strength, reduces scattering at the surface of the core and protects the fibre from absorbing surface contaminants.
