The refractive index of water is 1.33 and the speed of light in air is 3 x 108 ms-1. Answer. [1]:230 Light with linear polarization perpendicular to this axis will experience an ordinary refractive index no while light polarized in parallel will experience an extraordinary refractive index ne. Light from different points on the pencil, immersed in water refracts and appears to come from a point above the original position. (ii) Will the image be bigger or smaller than the object? Since intensity is proportional to the square of the electric field, it will depend on the depth into the material as exp(−4πκz/λ0), and the attenuation coefficient becomes α = 4πκ/λ0. If the electrons emit a light wave which is 90° out of phase with the light wave shaking them, it will cause the total light wave to travel slower. Distinguish between a real and a virtual image of an object. 1. is the complex modulus. A relatively high refractive index and low density can be obtained with glasses containing light metal oxides such as Li2O and MgO, while the opposite trend is observed with glasses containing PbO and BaO as seen in the diagram at the right. This implies that vacuum has a refractive index of 1, and that the frequency (f = v/λ) of the wave is not affected by the refractive index. λ This law is also known as Snell’s law of refraction. Rectilinear propagation of light and the law of reflection. Answer. What will be the focal length of this mirror? [Foreign] "Electromagnetic compression apparatus, methods and systems", differential interference contrast microscopy, Learn how and when to remove this template message, "Bestimmung des Brechungs und Farbenzerstreuungs Vermogens verschiedener Glasarten", "On the structure of doubly refracting crystals", "The Index of Refraction of Some Soda-Lime-Silica Glasses as a Function of the Composition", "Dispersion Properties of Optical Polymers", "Index of refraction of sapphire between 24 and 1060°C for wavelengths of 633 and 799 nm", "Forensic Science Communications, Glass Refractive Index Determination", "Development of Silica Aerogel with Any Density", "Intrinsically core-shell plasmonic dielectric nanostructures with ultrahigh refractive index", "Compression of electromagnetic waves by anisotropic medium. It is also the ratio of the sine of the angle of incidence and the sine of the angle of refraction, which is a constant for any given pair of media. To know more about Law of Reflection, visit here. 69. A change in birefringence alters the polarization and thereby the fraction of light that is transmitted through the second polarizer. A few examples are given in the adjacent table. 70. Here we see that κ gives an exponential decay, as expected from the Beer–Lambert law. Draw the following diagram in your answer book and show the formation of image of the object AB with the help of suitable rays. [52] In most circumstances κ > 0 (light is absorbed) or κ = 0 (light travels forever without loss). 39. (i) Convex mirror (ii) Concave mirror A concave lens has focal length of 20 cm. [Delhi (C)] A ray of light passing through the optical centre of the convex lens will continue to move along the same direction after refracting through the lens. To know more about Spherical Lenses, visit here. 9. Answer. 17. [Foreign] [All India] Dialogue Completion Q1( CBSE 2012 ): Read the following conversation and complete the dialogues by choosing the correct option. The refractive index n of the liquid can then be calculated from the maximum transmission angle θ as n = nG sin θ, where nG is the refractive index of the prism.[53]. If the height of the flame is 2 cm, find the height of its image. Draw a ray diagram and also state the position, the relative size and the nature of image formed by a concave mirror when the object is placed at the centre of curvature of the mirror. What would be the height of the image if the object is 5 cm high? Most commonly it is used to measure the concentration of a solute in an aqueous solution. The refractive index, represented by symbol n, is the velocity of light in vacuum divided by the velocity of light in a medium. [Foreign] The phase cannot be measured directly at optical or higher frequencies, and therefore needs to be converted into intensity by interference with a reference beam. Answer. (a) What is meant by ‘power of a lens’? It is indicated by the negative sign. 45. [Delhi] along -ve x-axis), are taken as negative. Pendry,J.B; Schurig,D. Lateral displacement in the diagram is BL. [3], The refractive index n of an optical medium is defined as the ratio of the speed of light in vacuum, c = 299792458 m/s, and the phase velocity v of light in the medium,[1]. This wave is typically a wave with the same frequency but shorter wavelength than the original, leading to a slowing of the wave's phase velocity. [Foreign] The incident ray, reflected ray and the normal all lie in the same plane. perpendicular to and below the principal axis are taken as negative. Molar refractivity, on the other hand, is a measure of the total polarizability of a mole of a substance and can be calculated from the refractive index as, where ρ is the density, and M is the molar mass.[34]:93. Pole (P): The midpoint or the symmetric centre of a spherical lens is known as its. Illustrate it with the help of a diagram. The coefficients are usually quoted for λ as the vacuum wavelength in micrometres. Define the focus of a concave mirror. However, there does not exist an overall linear relation between the refractive index and the density for all silicate and borosilicate glasses. `n_(12)=text(Speed of light in medium 2)/text(Speed of light in medium 1)`. Answer. To construct a ray diagram, we use two light rays which are so chosen that it is easy to know their directions after reflection from the mirror.