Two thick plates of uniaxial crystal, equally oriented and very little different in thickness, in the crossed nicols illuminate white light separately. Why can painting occur in the same environment, if you turn one plate relative to the other by 90º?
When the plates have the same orientation, the contributed path difference is big, i.e. corresponds to a high order of interference. In such conditions, the interference in white light, cannot be observed. If one of the plates is rotated with respect to another at 90 then the path difference will be the same, which is brought by a plate with a thickness equal to the thickness of the plates under consideration. With this difference in thickness the path difference can become so small that interference in white light will be possible.
I just wanted to say thank you guys so much for helping me get through my statistics class. Any area in math has never been my strong field and thanks to you guys I was still able to pass my course.
thanks to you and all the people on your team that helped in me passing my course. :-)