I'm really confused about something I was taught today in Physics.
So my understanding of polarisation is that essentially the wave is oscillating in loads of directions and when you used a polariser, it only lets waves oscillating in a specific direction through.
The textbook I had used the analogy of a rope and two gate posts to explain that if the grilles are vertical, it will only let the vertically oscillating part(s) of the wave through (which made sense from a mechanical point of view). The same when the grilles are horizontal; only the horizontally oscillating wave will pass through. I also looked at a few physics videos after the lesson which said the same thing.
Except my physics teacher said that analogy was actually the opposite of the truth. Apparently when the grilles are horizontal, only the vertically oscillating wave passes through (something to do with the direction of the electron oscillation that I really don't understand- someone please explain if so). I also looked at two videos from alevelphysicsonline on youtube- in one he supported the theory presented by the gate and then, in a much later video, he said the same as my physics teacher- that the gate analogy actually tells you the opposite of the truth.
Can someone explain to me which theory it is? It's really confusing me and I'm a little worried that if I write about either of them in my exam, the examiner will mark it as wrong. (my exam board is OCR-A)
What do you think?