A light of wavelength $500 \mathrm{~nm}$ is incident on a Young's double slit. The distance between slit and screen is $D=1.8 \mathrm{~m}$ and distance between slits is $d=0.4 \mathrm{~mm}$. If screen moves with a speed of $4 \mathrm{~m} / \mathrm{s}$, then with what speed first maxima will move?

Assertion : Distance between position of bright and dark fringe remain same in YDSE.

Reason : Fringe width, $\beta=\frac{\lambda D}{d}$

Assertion : Incoming light reflected by earth is partially polarised.

Reason : Atmospheric particle polarise the light.

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

Red light of wavelength 5400 $\mathop A\limits^o $ from a distant source falls on a slit 0.80 mm wide. Calculate the distance between first two dark bands on each side of central bright band in the diffraction pattern observed on a screen place 1.4 m from the slit.

Assertion : If a glass slab is placed in front of one of the slits, then fringe with will decrease.

Reason : Glass slab will produce an additional path difference.

An interference pattern is observed by Young’s double slit experiment. If now the separation between coherent source is halved and the distance of screen from coherent sources

A tube of sugar solution $20 \mathrm{~cm}$ long is placed between crossed nicols and illuminated with light of wavelength $6 \times 10^{-5} \mathrm{~cm}$. If the optical rotation produced is $13^{\circ}$ and the specific rotation is $65^{\circ}$, determine the strength of the solution.

In the given figure, $C$ is middle point of line $S_1 S_2$. A monochromatic light of wavelength $\lambda$ is incident on slits. The ratio of intensities of $S_3$ and $S_4$ is

The Young's double slit experiment is performed with blue and green light of wavelengths 4360 Å and 5460 Å respectively. If $x$ is the distance of 4th maxima from the central one, then

Assertion : Corpuscular theory fails in explaining the velocities of light in air and water.

Reason : According to corpuscular theory is that light should travel faster in denser media than rarer media.