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प्रश्न
How is polarisation of light obtained by scattering of light?
उत्तर
- The light from a clear blue portion of the sky shows a rise and fall of intensity when viewed through a polaroid that is rotated.
- This is because of sunlight, which has changed its I direction (having been scattered) on encountering the molecules of the earth’s atmosphere.
- The electric field of light interacts with the electrons present in the air molecules.
- Under the influence of the electric field of the incident wave the electrons in the molecules acquire components of motion in both these directions.
- We have an observer looking at 90° to the direction of the sun. Clearly, charges accelerating parallel do not radiate energy towards this observer since their acceleration has no transverse component.
- The radiation scattered by the molecule is therefore polarized perpendicular to the plane.
Polarisation by scattering
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संबंधित प्रश्न
Why does an unpolarised light incident on a polaroid get linearly polarised ?
A beam of unpolarised light is incident on a glass-air interface. Show, using a suitable ray diagram, that light reflected from the interface is totally polarised, when μ = tan iB, where μ is the refractive index of glass with respect to air and iB is the Brewster's angle.
Two polaroids P1 and P2 are placed with their pass axes perpendicular to each other. An unpolarised light of intensity I0 is incident on P1. A third polaroid P3 is kept in between P1 and P2 such that its pass axis makes an angle of 30° with that of P1. Determine the intensity of light transmitted through P1, P2 and P3
What is the Brewster angle for air to glass transition? (Refractive index of glass = 1.5)
What does a polaroid consist of? How does it produce a linearly polarised light?
Unpolarised light is incident on a polaroid. How would the intensity of transmitted light change when the polaroid is rotated?
A ray of ordinary light is travelling in air. It is incident on air glass pair at a polarising angle of 56°. Find the angle of refraction in glass.
Greenlight is an incident at the polarising angle on a certain transparent medium. The angle of refraction is 30°.
Find
(i) polarising angle, and
(ii) refractive index of the medium.
Light transmitted by Nicol prism is ______.
What is plane polarised light?
List the uses of polaroids.
State Brewster’s law.
What is the angle of polarisation and obtain the equation for an angle of polarisation?
Mention the types of optically active crystals with example.
An unpolarised light of intensity 32 Wm-2 passes through three Polaroids such that the axes of the first and the last Polaroids are at 90°. What is the angle between the axes of the first and middle Polaroids so that the emerging light has an intensity of only 3 Wm-2?
Polarisation of light is the only phenomenon that establishes ______.
Which of the following phenomena is not common to sound and light waves?
Can reflection result in plane polarised light if the light is incident on the interface from the side with higher refractive index?
To ensure almost 100 per cent transmissivity, photographic lenses are often coated with a thin layer of dielectric material. The refractive index of this material is intermediated between that of air and glass (which makes the optical element of the lens). A typically used dielectric film is MgF2 (n = 1.38). What should the thickness of the film be so that at the center of the visible spectrum (5500 Å) there is maximum transmission.
An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of light beam emerging from the analyzer is measured as 100 Lumens. Now, if the analyzer is rotated around the horizontal axis (direction of light) by 30° in clockwise direction, the intensity of emerging light will be ______ Lumens.
