Duduli

The rank of the tensor is the number of suffixes or indices(without counting an index which appears once as a subscript) in the symbol representing tensor.

It is a device which is used to produce the plane polarised light. It is based on the principle of selective absorption and more effective than the tourmaline crystal. Polaroid allows the light oscillations parallel to the transmission axis to pass through them. The crystal or polaroid on which the unpolarised light is incident is called polariser. Crystal or polaroid on which polarised light is incident is called analyser.