FOR STANDARD BYDEVENDRA KUMAR GIRIJA SHANKAR WHAT DO
( FOR STANDARD) BYDEVENDRA KUMAR GIRIJA SHANKAR
WHAT DO YOU OBSERVE IN THE PICTURE GIVEN BELOW ?
THE BROKEN EFFECT OF THE BRUSH AND THE TOY IS DUE TO REFRACTION.
EFFECT OF LIGHT WHEN LIGHT FALLS ON AN OBJECT IT IS PARTLY REFLECTED, PARTLY REFRACTED AND PARTLY ABSORBED. MAXIMUM REFRACTION OCCURS IN TRANSPARENT MEDIUM.
REFRACTION IS. . . BENDING OF LIGHT WHEN IT PASSES FROM ONE MEDIUM TO ANOTHER MEDIUM OF DIFFERENT OPTICAL DENSITY. DUE TO CHANGE IN VELOCITY OF LIGHT WHEN IT PASSES THROUGH MEDIUMS OF DIFFERENT OPTICAL DENSITIES. DUE TO CHANGE IN WAVELENGTH OF LIGHT WHEN IT PASSES THROUGH DIFFERENT MEDIUMS.
WAVELENGTH OF LIGHT CHANGES WHEN IT PASSES FROM ONE MEDIUM TO ANOTHER MEDIUM
LIGHT RAY MOVES AWAY FROM THE NORMAL WHEN IT TRAVELS FROM DENSER TO RARE MEDIUM. AIR r i WATER
LIGHT RAY MOVES TOWARD THE NORMAL WHEN IT PASSES FROM RARE TO DENSER MEDIUM. AIR i r WATER
REFRACTIVE INDEX FOR A GIVEN PAIR OF MEDIUMS WE DEFINE A CONSTANT FOR REFRACTION KNOWN AS REFRACTIVE INDEX. IT CAN BE DEFINED IN TERMS OF…. v. DEPTH v. VELOCITY v. SNELL’S LAW
REFRACTIVE INDEX IS DEFINED AS RATIO OF REAL DEPTH TO APPARENT DEPTH OF OBJECT IN THE MEDIUM. NORMAL O AIR WATER VIRTUAL OBJECT P ACTUAL OBJECT R
VELOCITY OF LIGHT IS DIFFERENT IN DIFFERENT MEDIUMS. AIR GLASS
VELOCITY OF LIGHT IS DIFFERENT IN DIFFERENT MEDIUM. AIR GLASS
REFRACTIVE INDEX OF A MEDIUM IS DEFINED AS THE RATIO OF VELOCITY OF LIGHT IN VACCUM TO VELOCITY OF LIGHT IN THE MEDIUM. µ=c/v
SNELL’S LAW: - n 1 sin θ 1=n 2 sin θ 2 where n 1, n 2 are refractive indices of medium 1 and 2 respectively θ 1, θ 2 are angle of incidence and angle of refraction
Observe the phenomenon of refraction when light ray passes from rarer medium to denser medium. Click to observe
REFRACTIVE INDEX OF WATER WITH Sin i RESPECT TO AIR = -----Sin r AIR i r WATER
Observe the phenomenon of refraction when light ray passes from denser medium to rare medium. Click to observe
CLICK TO INCREASE ANGLE OF INCIDENCE
CLICK TO INCREASE ANGLE OF INCIDENCE
CLICK TO INCREASE ANGLE OF INCIDENCE
CLICK TO INCREASE ANGLE OF INCIDENCE
The angle of incidence in the denser medium for which angle of refraction is 90º is known as “ CRITICAL ANGLE”. C
Refractive index of air with respect to glass = sin i / sin r = sin c / sin 90° Refractive index of glass with respect to air = sin 90°/sin c = 1 / sin c µ = 1/ sin c
What do you expect if angle of incident is greater than critical angle. ? To check your answer click. . MATERIAL CRITICAL ANGLE(DEGREE) DIAMOND 24. 5 FLINT GLASS 37 CROWN GLASS 41. 1 PLAIN GLASS 41. 2 WATER 48. 7 ICE 49. 8
CLICK TO INCREASE ANGLE OF INCIDENCE
CLICK TO INCREASE ANGLE OF INCIDENCE
CLICK TO INCREASE ANGLE OF INCIDENCE
TOTAL INTERNAL REFLECTION WHEN THE ANGLE OF INCIDENCE IN THE DENSER MEDIUM IS GREATER THAN THE CRITICAL ANGLE THE RAY UNDERGOES TOTAL INTERNAL REFLECTION. Ø Ø THAT IS , ALL THE INCIDENT LIGHT IS REFLECTED AND NO REFRACTION OCCURS.
TOTAL INTERNAL REFLECTION HAS MANY PRACTICAL APPLICATIONS: ØSPARKLING OF DIAMOND ØRAINBOW FORMATION ØOPTICAL FIBRE MIRAGE PERISCOPE AND BINOCULAR(PRISM)
Refraction of Light by Diamonds The brilliance of diamonds is due to their high refractive index, which is about 2. 4. The skill of the gem-cutter lies in angling the facets of the stone so that each light ray entering it is reflected many times before it emerges again. The refractive index is slightly different for each colour of light, so the light is split into its coloured components, giving rise to the multicoloured “fire” of diamonds.
MIRAGE IS FORMED WHEN LIGHT PASSES FROM COOLER AIR TO WARMER AIR AND IS BENT TOWARDS THE HORIZONTAL LINE OF VISION AND EVENTUALLY IT IS MADE TO TRAVEL UPWARDS BY TOTAL INTERNAL REFLECTION PRODUCING A VIRTUAL IMAGE.
OPTICAL FIBRE Fibre-Optic Cable A bundle of optical fibres passes easily through the eye of this needle. Fibreoptic cables are rapidly replacing bulky copper-wire cables in the telecommunications industry. A single pair of such cables can carry over a thousand conversations simultaneously.
Binoculars present a different view to each eye to enable a user to perceive depth. Each half of a pair of binoculars is essentially a telescope; however, binoculars often incorporate prisms so that they are more compact than a telescope of comparable power.
TO KNOW MORE ABOUT REFRACTION VISIT OUR WEBSITE “ OPTICA”
Mr. V. K SODHI ENCARTA. Freespace. virgin. net/garethjames/virtual/ optics/Refraction/refraction. html CLIP ART
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