GPO - Propagation and Velocity of Light - Topic 1 Flashcards
What is geometrical optics?
-This help us to understand the basics of light, reflection and refraction and the use of simple optical elements such as mirrors, prisms, lenses
•Also known as ray optics
What is Physical Optics?
- This help us to understand the phenomena of light wave, interference, diffraction, and polarization; the use of thin film coatings on mirrors to enhance or suppress reflection
- Also known as wave optics
what is the rectilinear propagation of light?
- Rectilinear propagation describes the tendency of electromagnetic waves to travel in a straight line.
- Light does not deviate when travelling through a homogeneous medium
What is Huygens’ Principle?
Christian Huygens, believed that light was made up of waves vibrating up and down perpendicular to the direction of the light travels, and therefore formulated a way of visualising wave propagation.
What is an optical medium?
Any space through which light travels
What are isotropic optical media?
Any optical media which has the same properties in all directions
What are homogeneous optical media?
Most optical media have these same properties throughout their mass
What are wave fronts?
When light starts out from a point source in an isotropic homogeneous medium, it spreads out uniformly at the same speed in all directions,
-Forming such imaginary spherical surfaces.
What is wavelength (λ)?
- Is the distance between successive points of similar phase
- For eg distance between two successive wave crests in the picture or between two successive troughs
- nm
What is frequency (ν)?
- Is the number of complete waves produced in one second
* Is expressed in cycle per second called hertz (Hz)
What is Amplitutde (A)?
- Is the peak valve of the wave
* Is a measure of height of the wave crest or depth of the wave trough
What is Velocity (v) ?
- It’s the rate at which the wave travels
- ms-1
What is the velocity of light in a vaccum and for all colours of light?
3 x 10^8 ms-1
What is the equation for velocity of light?
velocity of light = frequency x wavelength
v = ν λ
A group of light rays is called?
A pencil of rays