Topic 5 - Light And EM Flashcards
What is total internal reflection?
When light is completely reflected back at a boundary between two mediums
It occurs when light meets a less dense medium at an angle of incidence large than the critical angle.
What is the critical angle?
The angle of incidence which causes the angle of reflection to be 90 degrees
What determines the colour of visible light waves?
The wavelength and frequency of the light waves.
What colour of visible light has the highest frequency?
Violet
What colour of visible light has the largest wavelength?
Red
What is meant by the term “specular reflection”?
Rays are reflected from a smooth surface in a single direction.
What is meant by the term “diffuse reflection”?
Reflection from a rough surface which caused scattering of light rays.
How does a red colour filter work?
A red filter absorbs all wavelengths of light other than those in red range spectrum
This means only red light passed through the filter.
What is meant by “opaque”?
Not see-through
What governs the colour of an opaque object?
Different objects reflect different wavelengths of light by different amounts
The wavelengths that are most strongly reflected determine the colour
What happens to the wavelengths of lights that Aren’t reflected by an opaque object?
Wavelengths Absorbed by the object
What colour does an object appear if all wavelengths are reflected by equal amounts?
White
What colore does an object appear if all wavelengths are absorbed?
Black
What types of waves are EM waves.
Transverse
What do EM waves transfer?
Energy (not matter)