Air has a refractive index 1.0003. The thickness of air column, which will have one more wavelength of yellow light (6000 Å) than in the same thickness in vacuum is

Two points separated by a distance of 0.1 mm can just be inspected in a microscope when light of wavelength 6000 Å is used. If the light of wavelength 4800 Å is used, this limit of resolution will become

A beam of ordinary unpolarised light passes through a tourmaline crystal C₁ and then it passes through another tourmaline crystal C₂ which is oriented such that its principle plane is parallel to that of C₂. The intensity of emergent light is I₀. Now, C₂ is rotated by 60^o about the ray. The emergent ray will have an intensity

Light appears to travel in a straight line because

In Young's double slit experiment, the seventh maximum with wavelength λ₁ is at a distance d₁ and the same maximum with wavelength λ₂ is a distance d₂. Then d₁/d₂

Two coherent light sources S₁ and S₂ (λ = 6000 Å) are 1 mm apart from each other. The screen is placed at a distance of 25 cm from the sources. The width of the fringes on the screen should be

λ_a and λ_m are the wavelengths of a beam of light in air and in a medium respectively. If θ is the polarising angle, the correct relation between λ_a , λ_{m and θ is}

In Young's double slit experiment, let S₁ and S₂ be the two slits, and C be the centre of the screen. If∠S₁CS₂ = θ and λ is the wavelength, the fringe width will be

In a Young's double slit experiment the intensity at a point where the path difference is λ/6 (λ being the wavelength of the light used) is I. If I₀ denotes the maximum intensity. I/I₀ is equal to 

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