Polaroid are used

Polaroids are used in

Polaroids are used

Why are polaroids used in sunglasses?

Why are polaroids used in sunglasses?

If polaroids are to be used to avoid glares of in coming light then

In a series of polaroids placed in such a way that optical axis of each polaroid makes same angle with the next one. When unpolarized light falls on first and if no light is coming out from the last polaroid then by using how many number of polaroids in series this can be achieved :