Light waves can be polarised as they are

An unpolarized beam of intensity $2a^2$ passes through a thin polaroid. Assuming zero absorption in the polaroid,the intensity of emergent plane-polarized light is

$A$ plane polarised light passes through successive polarisers which are rotated by $30^{\circ}$ with respect to each other in the clockwise direction. Neglecting absorption by the polarisers and given that the first polariser's axis is parallel to the plane of polarisation of the incident light,the intensity of light at the exit of the fifth polariser is closest to

Which of the following diagrams represents the variation of the electric field vector magnitude with time for a circularly polarized light?

Plane-polarized light passes through a Polaroid. While observing through the Polaroid,it is seen that when the Polaroid completes one rotation about the direction of light,which of the following is observed?

The intensity of transmitted light when a polaroid sheet is placed between two crossed polaroids at $22.5^{\circ}$ from the polarization axis of one of the polaroids is (where $I_0$ is the intensity of polarized light after passing through the first polaroid):