A beam of unpolarised light of intensity \( I_0 \) is passed through a polaroid A and then through another polaroid B which is oriented so that its principal plane makes an angle of 45° relative to that of A. The intensity of emergent light is:
Two polaroide $A$ and $B$ are placed in such a way that the pass-axis of polaroids are perpendicular to each other Now, another polaroid $C$ is placed between $A$ and $B$ bisecting angle between them If intensity of unpolarized light is $I _0$ then intensity of transmitted light after passing through polaroid $B$ will be:
The center of a disk of radius $ r $ and mass $ m $ is attached to a spring of spring constant $ k $, inside a ring of radius $ R>r $ as shown in the figure. The other end of the spring is attached on the periphery of the ring. Both the ring and the disk are in the same vertical plane. The disk can only roll along the inside periphery of the ring, without slipping. The spring can only be stretched or compressed along the periphery of the ring, following Hooke’s law. In equilibrium, the disk is at the bottom of the ring. Assuming small displacement of the disc, the time period of oscillation of center of mass of the disk is written as $ T = \frac{2\pi}{\omega} $. The correct expression for $ \omega $ is ( $ g $ is the acceleration due to gravity): 
Let $ a_0, a_1, ..., a_{23} $ be real numbers such that $$ \left(1 + \frac{2}{5}x \right)^{23} = \sum_{i=0}^{23} a_i x^i $$ for every real number $ x $. Let $ a_r $ be the largest among the numbers $ a_j $ for $ 0 \leq j \leq 23 $. Then the value of $ r $ is ________.
Light travels in form of transverse EM waves. The underlying oscillation is along directions perpendicular to the propagation direction, in this example, oscillating electric and magnetic fields. Process of restricting the vibration of light waves to one direction is known as Polarisation.
There are three types of polarisation such as:
The few methods of polarisation of Light are: