A polarizer or polariser is an optical filter that lets light of a specific polarization pass and blocks waves of other polarizations. It can convert a beam of light of undefined or mixed polarization into a beam of well-defined polarization, that is polarized light. The common types of polarizers are linear polarizers and circular polarizers.
Length is a measure of one dimension, whereas area is a measure of two dimensions (length squared) and volume is a measure of three dimensions (length cubed).In most systems of measurement, the unit of length is a base unit, from which other units are defined.ength is a measure of one dimension, whereas area is a measure of two dimensions (length squared) and volume is a measure of three dimensions (length cubed).
1. the linear extent or measurement of something from end to end, usually being the longest dimension or, for something fixed, the longest horizontal dimension. 2. the extent of something from beginning to end, measured in some more or less regular units or intervals: the book was 600 pages in length.