Why can't be same plane?

Question

In polarisation by reflection, why the polarised reflected light must be perpendicular to the plane of incidence(surface of paper)?
Extremely confusing.

Dear JimWV, i not really understand about your explanation. But very TQ, i'll try to understand it.

Answer 1

This is alittle hard to explain in words (without drawings) but let me try. Light is a wave motion. Just imagine that you and a friend were holding a jump rope and that one of you moved your hand up and down to make a wave. You could also move your hand from one side to the other to make a wave parallel to the ground. In fact by moving your hand in various directions you can make a wave which moves in any direction in relation to the ground. Light waves which come, say, from the sun are said to be unpolarized. They move in all directions throughout 360 degrees from a surface. Now. Imagine you and your friend were on opposite sides of a picket fence. You know, one with up and down slats. Imagine that the rope was threaded between two slats of the fence. Now, you would be able to make a wave only by moving your hand up and down. If you tried moving your hand sideways the wave would be stopped at the fence. Some materials which we lump together under the name polaroid or polarizing filters do just this. They allow light waves to pass through only if they vibrate in only one direction. The unpolarized light which hits such material is said to be polarized so it vibrates in only one plane. This is the way polaroid sunglasses work. Light which reflects from horizontal surfaces like a wet street or a lake at sunset or even your lab desk top is polarized in the plane of the surface -- horizontally. Like moving the rope left and right. Sunglasses are polarized vertically like the picket fence. The glare of the reflected light is effectively stopped by the polaroid material while light polarized in other directions passes through. Ask your teacher if he/she has two matching polaroid filters. If you place one over the other and turn them so that they are polarized at right angles to each other no light or at least a very small amount of dark purple light will pass through. Do you see why? Imagine you, the rope, and your friend again. This time imagine that between you were two picket fences turned at right angles to each other so the slats of one went up and down while the slats of the other went left and right. There would be only a small opening where two slats crossed for your rope to pass through and try as you may however you wiggled the rope no wave would pass through. I know this was long and difficult but reread it several times and maybe even find a picket fence and try it. It will be well worth understanding.

Answer 2

I'm not sure exactly what you are asking here, but light that is polarised by the act of reflection absolutely is not at perpendicular incidence. The maximum polarisation occurs at the Brewster angle, which varies by substance.

Answer 3

If you throw a tennis ball at the gym floor, do you expect it to bounce back in your face, or continue in the direction you threw it? You know it, not confusing, just think one step at a time.

Jonnie

Answer 4

cant help you there li mei