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प्रश्न
The refractive index of air with respect to glass is expressed as `""_g μ_a=sin i /sin r`.
- Write down a similar expression for aμg in terms of the angles i and r.
- If angle r = 90°, what is the corresponding angle i called?
- What is the physical significance of the angle i in part (b)?
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उत्तर
- R.I of glass w.r.t. air `= ""_aμ_g = sini/sinr`
∠r is angle of incidence in air
∠i is angle of refraction in medium - When angle r = 90°
∴ sin 90° = 1 in air
Angle i in medium is called the critical angle. - The significance of ∠i = ic = critical angle is:
The refractive index of the denser medium relative to the rarer medium can be computed using the critical angle value.
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संबंधित प्रश्न
When a ray of light travels from air to glass slab and strikes the surface of separation at 90°, then it …………….
(a) bends towards normal
(b) bends away from normal
(c) passes unbent
(d) passes in zigzag way
How is the refractive index of a medium related to the speed of light in it?
For which colour of white light, is the refractive index of a transparent medium the most?
Four students A, B, C and D traced the paths of incident ray and the emergent ray by fixing pins P and Q for incident ray and pins R and S for emergent ray for a ray of light passing through a glass slab.
The correct emergent ray was traced by the student:
(1) A
(2) B
(3) C
(4) D
Choose the correct alternative and rewrite the following:
A glass slab is placed in the path of convergent light. The point of convergence of light
Which colour of light travels fastest in any medium except air?
How is the refractive index of a medium related to its real depth and apparent depth?
You are provided with a printed piece of paper. Using this paper how will you differentiate between a convex lens and a concave lens?
After a robbery, if a window has been broken, there will be tiny particles of glass. Some of these will be found at the scene of the crime and some may be caught in the thief’s clothing. If the police can prove that these particles are identical, they have a strong case.
A method of doing this is to suspend the particles of glass in a special liquid. Light of a single colour is thrown through the liquid and the particles viewed through a microscope. The temperature of the liquid is then slowly altered. This alters the speed of light through the liquid (i.e., it alters the refractive index). At one particular temperature, the particles of glass disappear. It this happens at the same temperature for both sets of glass particles, they probably came from the same broken pane of glass.
Complete and copy the diagram to show how light bends when it travels from the liquid to the glass and back to the liquid, If the light slows down in the glass.
