When a light beam passes through a polarizer filter, it gets linearly polarized. When this linearly polarized light passes through analyser, its intensity depends on the angular position of the analyser. The maximum light intensity is transmitted when the optical axis of polarizer and analyser coincide. The intensity of transmitted beam is defined by Malus law:
$$I = I_{0} \cos^{2} \theta$$ Where:\(I_{0}\) = Intensity of incident light
\(\theta\) = Angle between the optical axis of the polarizer and analyser