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प्रश्न
During sunset and sunrise, the sun is seen when it is slightly below the horizon. Give reason.
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उत्तर
Light rays from the sun while coming towards earth suffers successive refractions from a rarer to a denser medium and so it bends towards the normal at each refraction. These rays on earth appear to be coming from an apparent position of the sun which is higher than its actual position. Thus, the sun is seen even when it is slightly below the horizon during sunset and sunrise.
संबंधित प्रश्न
Write a short note on dispersion of light.
A student traces the path of a ray of light passing through a rectangular glass slab and marks the angle of incidence i, angle of refraction r and angle of emergence e, as shown.
The correctly marked angle(s) is/are
(A) ∠ i only
(B) ∠ e only
(C) ∠ r only
(D) ∠ i and ∠ e
The speed of light in glass is 2 × 105 km/s. What is the refractive index of glass?
Draw the diagram given below and clearly show the path taken by the emergent ray.
Draw diagrams to show the refraction of light from glass to air. In diagram, label the incident ray, refracted ray, the angle of incidence (i) and the angle of refraction (r).
A light ray in passing from water to a medium
(a) speeds up
(b) slows down. In each case, give one example of the medium.
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)?
What is the correct reason for blinking / flickering of stars? Explain it.
a) The blasts in the stars.
b) Absorption of star light by the atmosphere.
c) Motion of the stars.
d) Changing refractive index of gases in the atmosphere.
Does the depth of a tank of water appear to change or remain the same when viewed normally from above?
The path of a ray of light coming from air passing through a rectangular glass slab traced by four students are shown as A, B, C and D in the figure. Which one of them is correct?
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| A | B | C | D |
