polarisation Flashcards
define polarisation
Particle oscillations occur in only one of the directions perpendicular to the direction of wave propagation
which waves can polarisation occur in and why?
transverse because they oscillate in any plane that is perpendicular to the propagation direction.
however, when transverse waves get polarised what does this mean?
- vibrations are restricted to about one direction
- these vibrations are therefore so still perpendicular to the direction of propagation/energy transfer
why can’t longitudinal waves be polarised?
the oscillations are parallel to the direction of energy transfer
how can waves (including light) be polarised?
using a polariser or a polarising filter which only transmits vibrations in a single direction therefore allows oscillations in a certain plane to be transmitted. if you have two polarising filters at right angles to eachs other,
no light will get through therefore
explain what happens whenever unpolarised light comes into contact with a vertical transmission axis/polariser
only light with vibrations in line with the filter’s transmission axis (in this case it is vertical) can pass through the so first filter.
if the polariser is rotated 90 degrees, what will happen?
transmission axis horizontal, therefore the vertically polarised light is passing through a filter with a transmission axis perpendicular to the wave, resulting in none of the light passing through
how can light be polarised?
through reflection, refraction and scattering of waves.
describe how to investigate light intensity but instead with two polarisers/ polarising filters A and B with their transmission axes parallel
if an unpolarised light source is placed in front of two identical polarising fliters, A and B, with their transmission axise parallel then filter A will polarise the light in a certain axis and all of the polarised light will be passing through unaffected
in this case, the maximum intensity of light is transmitted
