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प्रश्न
Why do the faces of persons sitting around campfire appear to shimmer?
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उत्तर
The rays coming from the face of the person, sitting across the campfire, suffer refraction on passing through hot air. Thus, we see the apparent image of the person. Since hot air is in motion, therefore its optical density changes, which in turn shifts the image rapidly. This rapidly shifting image gives a shimmering effect.
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
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In fig 4.18, name the ray which represents the correct path of light while emerging out through a glass block.
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(i) Name the lens formed by the combination.
(ii) What is the line XX' called?
(iii) Complete the path of the incident ray PQ after passing through the lens.
(iv) The final emergent ray either meets XX' at a point or appears to come from a point on XX'. Label it as F, What is this point called?
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(a) Name the phenomenon that is taking place.
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(c) What radiation would you detect above X and below Y?
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What should be the ratio of the speed of light through the liquid to the speed through the glass so that there is no refraction of light at the boundaries of the glass block when the system is illuminated by the light of one colour?
Two parallel rays of Red and Violet travelling through the air, meet the air-glass boundary as shown in the above figure. Will their paths inside the glass be parallel? Give a reason for your answer.
A ray of light strikes the surface of a rectangular glass slab such that the angle of incidence in air is
- 0°,
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In each case, draw a diagram to show the path taken by the ray as it passes through the glass slab and emerges from it.
