Brewster's Law:
Brewster's observed that when unpolarised light is incident on the material, reflected and refracted rays are at the angle of 90o as shown in Figure given below. By using Snell's law, we know that refractive index of the material is provided by relation
μ = sin ip/sin r
Here ip is the polarizing angle. It is stated as angle of incidence when reflected light is almost entirely polarized. μ is refractive index of material.
But from the Figure, one can see that r = 90 - ip
μ = sin ip /sin (90 - ip) = sin ip /cos ip = tan ip
Therefore Refractive index μ = tan ip................Eq.1
Eq.1 is known as Brewster's law. Thus, refractive index of the transparent medium is equal to tangent of the polarizing angle ip. Therefore Eq.1, (Brewster law) can be utilized to determine refractive index of materials.
Percentage of Polarization:
When light passes through the Polaroid (or polarizer), light that has vibration along specified direction of crystal above is transmitted. If transmitted light intensity is estimated using the photocell, current measured remains constant in whatever direction polarizer is rotated. If there is any variation in intensity, it illustrates that incident light is partly polarized. I.e., vibration of the incident beams is not uniform in all directions.
P = [(Imax - Imin)/(Imax x Imin)] x 100.............................Eq.2
Where Imax = maximum light intensity
Imin = minimum light intensity
Malu's Law:
The Analyzer is introduced between the polarizer and photo cell. Specified direction of polarizer makes an angle Θ with an analyzer being oriented vertically. Polarized light transmitted by polarizer can be resolved into 2 components, thus, Eocos Θ vertically and Eo sin Θ horizontally, as shown in Figure given above, where Eo is an amplitude vector of th incident beam. Only component of amplitude Eo cos Θ that is parallel to transmission direction, would be transmitted by an analyzer. The transmitted light is maximum when Θ is 0o and is zero (minimum) when Θ is 900. At intermediate angles, intensity is proportional to amplitude, and we have
I0 α E02 and I α E2
Therefore I/I0 = E2E0 = E02 cos2Θ/ E02
Therefore I = I0cos2Θ.....................Eq.3
The Eq.3 is called as Malu's law
Thus from Eq.3, it can be observed that intensity of emergent light differs as square of the cosine of angle between polarizer and the analyzer.
Application of Polarization:
(i) Use of Polaroids in Sunglasses:
Unpolarised light is injurious to human eye, but with the use of Polaroid this can be avoided. They protect our eyes from glare. They assisted to decrease intensity of sunlight.
(ii) In Film Industries:
Polarized light is utilized in films to generate illusion of three dimensional pictures.
(c) Saccharimetry:
The rotation of plane of polarization by sugar solution is utilized as a method of finding the concentration of sugar solution in the given sample.
(d) Photoelectric Stress Analysis:
Few substances like glass and plastic, which are not usually double refracting, may become so if subjected to stress. If such stressed materials are put between the polarize and analyzer, bright and dark areas which are seen give information about strains. Technology of photo-elasticity is based on double refraction generate by stresses.
(e) Utilized in window pares:
Window panes of airplane and trains utilized polaroids to manage light entering through them.
Tutorsglobe: A way to secure high grade in your curriculum (Online Tutoring)
Expand your confidence, grow study skills and improve your grades.
Since 2009, Tutorsglobe has proactively helped millions of students to get better grades in school, college or university and score well in competitive tests with live, one-on-one online tutoring.
Using an advanced developed tutoring system providing little or no wait time, the students are connected on-demand with a tutor at www.tutorsglobe.com. Students work one-on-one, in real-time with a tutor, communicating and studying using a virtual whiteboard technology. Scientific and mathematical notation, symbols, geometric figures, graphing and freehand drawing can be rendered quickly and easily in the advanced whiteboard.
Free to know our price and packages for online physics tutoring. Chat with us or submit request at [email protected]
Theory and lecture notes of Interest Rates and Aggregate Demand all along with the key concepts of Interest Rates, Aggregate Demand, Investment as a Share of Real GDP, Importance of Investment. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Interest Rates and Aggregate Demand.
tutorsglobe.com glaucoma and nyctalopia assignment help-homework help by online lens replacement tutors
thermodynamic stability-reaction of complex tutorial all along with the key concepts of chelate effect, kinetics and mechanisms of complexes, reaction mechanism in complexes and expression for rate law
Planktonic benthic invertebrates tutorial all along with the key concepts of Benthic Organisms, Infauna, Epifauna, Demersal, Epifaunal Benthos, Common Nature of Benthic Invertebrates, Significance of Benthic Invertebrates
For accounting information to be helpful, the accountant must be unambiguous for whom the information is being ready and for what is the purpose of information that will be used.
Camera is a device that is used to capture images (generally photographs), either singly or in sequence, with or with no sound, success along with video cameras.
tutorsglobe.com economic importance assignment help-homework help by online biology in human welfare tutors
Theory and lecture notes of Cost Concepts for Decision Making all along with the key concepts of Costs, Cost-Minimization Problem, iso-cost curve, Expansion Path, Comparative Statics Analysis, Cost Minimization in SR, Backing Out. Tutorsglobe offers homework help, assignment help and tutor’s assistance on cost concepts for decision making.
www.tutorsglobe.com offers answering questions to shut-down situations in short-run, perfect competition assignment help - homework help by online tutor;s help.
tutorsglobe.com average variable cost assignment help-homework help by online short run average cost curves tutors
tutorsglobe.com energy and enzymes assignment help-homework help by online general microbiology tutors
Fermentation tutorial all along with the key concepts of History of fermentation, Classification of fermentation, Microbial fermentation, Enzymatic fermentation, Fermentation Process, Product recovery and purification during fermentation
Theory and lecture notes of Relationship to operating system all along with the key concepts of relationship to operating system, sample system, approaches of operating system. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Relationship to operating system.
tutorsglobe.com farming techniques assignment help-homework help by online poultry tutors
Diffraction and Resolution tutorial all along with the key concepts of Diffraction and Image formation, Resolving power of Optical instruments, Resolving Power of Astronomical Telescope, Resolving Power of Microscope and X-ray diffraction
1946739
Questions Asked
3689
Tutors
1471994
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!