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प्रश्न
List the uses of polaroids.
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उत्तर
- Polaroids are used in goggles and cameras to avoid glare of light.
- Polaroids are useful in three dimensional motion pictures i.e., in holography.
- Polaroids are used to improve contrast in old oil paintings.
- Polaroids are used in optical stress analysis.
- Polaroids are used as window glasses to control the intensity of incoming light.
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संबंधित प्रश्न
For a glass plate as a polariser with refractive index 1.633, calculate the angle of incidence at which light is polarised.
If the critical angle of a medium is sin-1(3/5), find the polarising angle.
Show, using a simple polaroid, that light waves are transverse in nature. Intensity of light coming out of a polaroid does not change irrespective of the orientation of the pass axis of the polaroid. Explain why.
Find an expression for intensity of transmitted light when a polaroid sheet is rotated between two crossed polaroids. In which position of the polaroid sheet will the transmitted intensity be maximum?
Show, via a suitable diagram, how unpolarised light can be polarised by reflection.
Two polaroids P1 and P2 are placed with their pass axes perpendicular to each other. 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 60° with that of P1. Determine the intensity of light transmitted through P1, P2 and P3.
What is the value of refractive index of a medium of polarising angle 60°?
The glass plate of refractive index 1.732 is to be used as a polarizer, its polarising angle is _______.
What does a polaroid consist of? How does it produce a linearly polarised light?
The transverse nature of light is shown in ______.
What is a analyser?
What is plane polarised light?
State and obtain Malus’ 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.
What is normal focusing?
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?
The reflected light is found to be plane polarised when an unpolarized light falls on a denser medium at 60° with the normal. Find the angle of refraction and critical angle of incidence for total internal reflection in the denser to rarer medium reflection.
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.
