polarisation Flashcards
What is polaristation
understand that polarisation is a phenomenon associated with transverse waves
what is Malus’s law
Malus’s law (I = I0 cos² θ)
Intensity of emerging polarised light = intensity of polarised light falling on the analyser x cos² x the angle between the axis of the incident polarised light and the axis of the analyser
How to calculate the intensity of a plane polarised electromagnetic wave after transmission through a polarising filter or a series of polarising filters
recall and use Malus’s law (I = I0 cos2θ) to calculate the intensity of a plane polarised electromagnetic wave after transmission through a polarising filter or a series of polarising filters
why does it appear that waves vibrate in all directions
Each quantum of light emitted by a source of light has vibrations in one plane but because you receive many millions of quanta per second from a light source it appears that the wave is vibrating in all directions.
What is an unpolarised wave
A wave in which the plane of vibration is constantly changing is called an unpolarised wave.
what does plane polarised mean
If the vibrations of a transverse wave are in one plane only then the wave is said to be plane polarised.
What happens when light is plane-polarised
When light is plane-polarised the vibrations are made to occur in one plane only. Light is a transverse electromagnetic wave with the vibrations of an electric and a magnetic field occurring at right angles to each other and in any plane at right angles to the direction of travel of the light.
what type of waves can be polarised
transverse waves can be polarised, longitudinal waves cannot.
Effects of polarisation
Sunglasses, Car windscreens, Polarisation by reflection - glare/shine off roads, Optical activity, Polarisation of scattered sunlight, Stresses in materials, Liquid crystal displays on a calculator, Lap top displays
what does Malus’ law states
“the intensity of plane-polarized light that passes through an analyzer varies as the square of the cosine of the angle between the plane of the polarizer and the transmission axes of the analyzer”.
