Refraction and Prism Essay Sample

Purpose:
I ) To look into the dependance. of the angle of divergence on the angle of incidence. utilizing a hollow prism filled one by one with different crystalline fluids. two ) And happen the velocity of visible radiation in given crystalline fluids.

Apparatus REQUIRED:
Pulling board. white sheets of paper. hollow prism. different liquids ( H2O. kerosine. oil. spirit etc ) pulling pins. pencil. half metre graduated table. thumb pins. graph documents and a protractor.

Introduction:
In optics. a prism is a crystalline optical component with level. polished surfaces that refract light. The exact angles between the surfaces depend on the application. The traditional geometrical form is that of a triangular prism with a triangular base and rectangular sides. and in conversational usage “prism” normally refers to this type. Some types of optical prism are non in fact in the form of geometric prisms. Prisms can be made from any stuff that is crystalline to the wavelengths for which they are designed. Typical stuffs include glass. plastic and fluorspar. A prism can be used to interrupt light up into its constitutional spectral colourss ( the colourss of the rainbow ) . Prisms can besides be used to reflect visible radiation. or to divide light into constituents with different polarisations.

PRISM AND NATURE OF LIGHT:
Before Isaac Newton. it was believed that white visible radiation was colourless. and that the prism itself produced the colour. Newton’s experiments demonstrated that all the colourss already existed in the visible radiation in a heterogenous manner. and that “corpuscles” ( atoms ) of visible radiation were fanned out because atoms with different colourss traveled with different velocities through the prism. It was merely subsequently that Young and Fresnel combined Newton’s atom theory with Huygens’ wave theory to demo that colour is the seeable manifestation of light’s wavelength. Newton arrived at his decision by go throughing the ruddy colour from one prism through a 2nd prism and found the colour unchanged. From this. he concluded that the colourss must already be present in the entrance light — therefore. the prism did non make colourss. but simply separated colourss that are already at that place. He besides used a lens and a 2nd prism to recompose the spectrum back into white visible radiation.

This experiment has become a authoritative illustration of the methodological analysis introduced during the scientific revolution. The consequences of this experiment dramatically transformed the field of metaphysics. taking to John Locke’s primary V secondary quality differentiation. Newton discussed prism scattering in great item in his book Opticks. [ 1 ] He besides introduced the usage of more than one prism to command scattering. [ 2 ] Newton’s description of his experiments on prism scattering was qualitative. and is rather clear. A quantitative were introduced in the 1980s. [ 3 ]

Theory:
HOW DOES A PRISM Work:
Light alterations speed as it moves from one medium to another ( for illustration. from air into the glass of the prism ) . This velocity alteration causes the visible radiation to be refracted and to come in the new medium at a different angle ( Huygens rule ) . The grade of bending of the light’s way

depends on the angle that the incident beam of light makes with the surface. and on the ratio between the refractile indices of the two media ( Snell’s jurisprudence ) . The refractile index of many stuffs ( such as glass ) varies with the wavelength or colour of the visible radiation used. a phenomenon known as scattering. This causes visible radiation of different colourss to be refracted otherwise and to go forth the prism at different angles. making an consequence similar to a rainbow. This can be used to divide a beam of white visible radiation into its constitutional spectrum of colourss. Prisms will by and large scatter visible radiation over a much larger frequence bandwidth than diffraction grates. doing them utile for broad-spectrum spectrometry. Furthermore. prisms do non endure from complications originating from overlapping spectral orders. which all grates have. Prisms are sometimes used for the internal contemplation at the surfaces instead than for scattering. If light inside the prism hits one of the surfaces at a sufficiently steep angle. entire internal contemplation occurs and all of the visible radiation is reflected. This makes a prism a utile replacement for a mirror in some state of affairss.

A triangular prism. scattering visible radiation ; waves shown to exemplify the differing wavelengths of visible radiation.

Angle of Minimum Deviation:
A ) Defination: The minimal value of angle of divergence. is called angle of minimal divergence. It is represented by the symbol Dm.

B ) Explanation: For same angle of divergence ( D ) there are two values of angle of incidence. One value equals ’i’ and other value peers ‘e’ As angle ‘i’ is increased from a little value. ‘e’ lessenings from big value and angle of divergence lessenings. When angle of divergence is minimal ( Dm ) . so. ‘i’ and ‘e’ becomes equal.

Diagram:

Which of these images should we take for the undertaking. . ? ? ?

TYPES OF PRISM:
Diffusing prisms

Comparison of the spectra obtained from a diffraction grate by diffraction ( 1 ) . and a prism by refraction ( 2 ) . Longer wavelengths ( ruddy ) are diffracted more. but refracted less than shorter wavelengths ( violet ) . Chief article: Diffusing prism

Diffusing prisms are used to interrupt up light into its constitutional spectral colourss because the refractile index depends on frequence ; the white visible radiation come ining the prism is a mixture of different frequences. each of which gets dead set somewhat otherwise. Blue visible radiation is slowed down more than ruddy visible radiation and will hence be set more than ruddy visible radiation.

Observation:
As given in the practical book on page no. 256

Calculation:
What should we make in the calculations… ? ? Should we travel harmonizing to the expression given in the book. . ? ?

Graph:
Graph between angle of incidence and angle of divergence.

Consequence:

1. The i-D graph indicates that as the angle of incidence ( I ) increases. the angle of divergence ( D ) nfirst lessenings. attains a minimal value ( Dm ) and so once more get down increasing for farther addition in angle of incidence. 2. The angle of minimal divergence for a ) H2O Dm= O

B ) kerosine or glycerol Dm= degree Celsius ) spirit Dm=

vitamin D ) gum terpentine oil Dm=

3. The refractile indices of the a ) H2O n= B ) kerosine or glycerol n= degree Celsius ) spirit n= vitamin D ) gum terpentine oil n= 4. Speed of visible radiation a ) H2O v= m/s m/s

B ) kerosine or glycerol v= degree Celsius ) spirit v= m/s vitamin D ) gum terpentine oil v= m/s

Doubts:
Ma’am can we utilize glycerine alternatively of kerosine and the remainder liquids are oil. spirit and water… And anything else that we should include in the project… ? ? ? Is any more information required for the undertaking or this is adequate. . ? ? ?