polarisation Flashcards
In which waves can polarisation only happen in
EM waves
define plane of the wave for EM waves
Plane of oscillation of the electric field
Is the light from sun or light from bulb unpolarised
both are unpolarised
What does it mean that the light from sun or bulb is unpolarised
It means light contains a mixture of waves where the electric field could be oscillating in any plane directions.
air draw a unpolarised wave
vectors from Origin in all directions and arrows on both ends
air draw a polarised wave
vectors from Origin in 1 direction and arrows on both ends
what does a plane polarised wave mean
a wave that has fields in only one plane
can longitdunial waves be polarised
no as not at right angles
What structure do some materials have that can be used as polarising filters
crystaline structure
What do polarising filters do
These only allow oscillations in one plane to pass through.
What does malus’ law state
when a perfect polariser is put in a beam of polarised light, the intensity I, of the light that passes through it is given by
i = i max COS^2
Where i is intensity transmitted at angle theta.
what is i max
i max is the maximum intensity transmitted when theta is 0
what degree does the analyser have to be in so that no light passes through
90 degrees
because cos^2 x 90 = 0
so i = i max cos^2 = 0
what direction is wave coming at from microwave transmitter in the expriment, vertical or horizontal.
horizontal
what happens to the microwave waves when they go through the metal grill when the grill is at a horizontal, and will the ammeter connected to the microwave reciever give high or low output.
the metal grill acts as a horizontal polariser, because waves are already at horizontal, it will just go through, and very few will be absorbed, so the reading in ammeter in the microwave reciever is going to be very high.
