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.