Polarisation Flashcards
What is meant by a plane-polarised wave
when unpolarised light is polarised, the electric field oscillations occur in only one plane. This is the plane of polarisation
The effect on light of polarisers and analysers
if two polarisers with the same orientation transmit light in the same plane.
if one is rotated 90° then light is blocked where they overlap.
when a ray of unpolarised light is incident on the surface of an insulator at Brewster’s angle the reflected ray becomes
plane-polarised
Derivation of n=taniₚ
n=siniₚ/sinr but iₚ +r = 90° so n = siniₚ/sin(90-iₚ) thus n=siniₚ/cosiₚ so n =taniₚ
n=taniₚ
n = refractive index iₚ = Brewster's angle (°)
how would you arrange two polarising filters so that the two images do not interfere
they should be arranged 90° to each other
How does an arrangement which contains two polarising filters, one for each eye, enable a different image to be seen by each eye
One filter will let through the vertically polarised light and will block the horizontal
and
The other filter will let through horizontal light and block the vertical
Light from a lamp
is unpolarised light
Light from a screen such as a tv, or cinema screen
is polarised light
When a filter is rotated 90° when looking through at a lamp what is the change in brightness
there is no change as the lamp is unpolarised light
If you look at a screen through one filter and rotate it 90° there will be no brightness change why?
As there is only one filter the image from one plane will decrease and the image from the other will increase, thus the brightness stays the same
what would happen when two polarising filters are rotated 180°
it would be at its minimum brightness at 90°
it would be at its maximum brightness at 180°
if a polariser is removed from two filters and it is rotated 180° what would happen
the brightness remains constant
how do polarising sunglasses reduce the glare compared to non-polarising sunglasses
The polarising sunglasses will act as an analyser and block the glare.
to find the angle of refraction when you have brewster’s angle you must
refraction angle = 90 - brewster’s angle