Polaroids, Polarization by reflection and refraction Polarization by Scattering

Lesson 14 of 17 • 0 upvotes • 12:28mins

Rajesh Kumar

Polaroids,Polarization by reflection and refraction,Polarization by Scattering. Polaroids method by which unpolarised light converted into polarised light, instrument used known as polarizer .plane seat of circular shape known as disc also known as polaroids. polaroids transmit light, electric field vector parallel to special direction in the sheet .polaroids consists of long Chains of hydrocarbons ,conducting at optical frequency .light falls perpendicular on the sheet and electric field parallel to chain ,which absorbed electric current in the chain. when light perpendicular to chain gets transmitted to transmission axis of the polaroid. when light passes through the polaroid the transmitted light becomes linearly polarized with electric vector parallel to the transmission Axis. when E- vector parallel to T- axis then completely transmitted by the polaroid and when perpendicular then completely stopped . when a vector is at angle theta with TAxis then partially transmitted the intensity of light is I is equal to I° cos squared theta ,known as law of malus. I° is the intensity when the incident E vector is parallel to the Taxis . polarization by reflection and refraction : incident, reflected and refracted ray all are in one plane plane of incidence here is xy plane . when arrow size reduced and dot same size then reflection in xy plane ,electric component . when Arrow same size and the dog reduced in refracted case. If tani= μ ,reflected light is completely polarized with electric field in Z direction .refracted light never completely polarized. the angle i called Brewster angle ,then known as brewster's law . reflected light is polarised used in preparing sunglasses which reduce the glare from roads, snow, water surfaces. Sun glasses are polaroids . TAxis perpendicular to the director of the polarized reflected light. which is responsible for the Glare is the largely absorbed. ordinary dark coloured sunglasses which absorb any light passing through them which reduce the intensity to a large extent. polarisation by scattering unpolarised light scattered by small particles light is partially polarised. the blue light received from the sky is partially polarized . human eye does not distinguish between an unpolarized light and polarised light. the eyes of a bee can detect the difference. also can determine the direction of polarization