When unpolarised light is passed through crossed polaroids, then light passing through the first polaroid:

$A$ beam of light of intensity $I_0$ falls on a system of three polaroids which are arranged in succession such that the pass (transmission) axis is turned through $60^{\circ}$ with respect to the preceding one. The fraction of the incident light intensity that passes through the system is $\left(\cos 60^{\circ} = 1/2\right)$.

Unpolarised light of intensity $32 \, W m^{-2}$ passes through a combination of three polaroids such that the pass axis of the last polaroid is perpendicular to that of the pass axis of the first polaroid. If the intensity of the emerging light is $3 \, W m^{-2}$,then the angle between the pass axis of the first two polaroids is $............ \, ^{\circ}$.

An unpolarised beam of intensity $2 a^{2}$ passes through a thin polaroid. Assuming zero absorption in the polaroid,the intensity of emergent plane polarised light is

Two polaroids are placed in the path of an unpolarised light beam of intensity $I_0$ such that no light is emitted from the second polaroid. If a third polaroid,whose polarisation axis makes an angle $\theta$ with that of the first polaroid,is placed between the polaroids,then the intensity of light emerging from the last polaroid is

When a plane-polarised light is passed through an analyser and the analyser is rotated through $90^{\circ}$,the intensity of the emerging light