Two polaroids have their polarizing directions parallel so that the intensity of the transmitted light is maximum. The angle through which either polaroid must be turned so that the intensity of the transmitted light is dropped to one-half of the previous transmitted intensity is $.....^\circ$.

$A$ source of light is placed in front of a screen. The intensity of light on the screen is $I.$ Two Polaroids $P_{1}$ and $P_{2}$ are placed between the source of light and the screen such that the intensity of light on the screen is $I/2.$ By what angle (in degrees) should $P_{2}$ be rotated so that the intensity of light on the screen becomes $3I/8?$

An unpolarised light beam of intensity $2 I_{0}$ is passed through a polaroid $P$ and then through another polaroid $Q$ which is oriented in such a way that its passing axis makes an angle of $30^{\circ}$ relative to that of $P$. The intensity of the emergent light is.

Longitudinal waves cannot

An unpolarized light beam of intensity $I_0$ is incident on a polarizer $A$ and then passed through a second polarizer $B$. If the principal plane of polarizer $B$ makes an angle of $45^\circ$ with respect to polarizer $A$,the intensity of the emerging light will be ........

Define unpolarized light and polarized light.