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प्रश्न
Why is the colour red used as a sign of danger?
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उत्तर
Red colour is used as a sign of danger due to its greater wavelength and lesser deviation (scattering).
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संबंधित प्रश्न
Write a short note on dispersion of light.
Four students P, Q, R and S traced the path of a ray of light passing through a glass slab for an angle of incidence 40° and measured the angle of refraction. The values as measured them were 18°; 22°; 25° and 30° respectively. The student who has performed the experiment methodically is
(A) P
(B) Q
(C) R
(D) S
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).
How does the angle of minimum deviation produces by a prism change with increase in :
the refracting angle of prism?
A postage stamp kept below a rectangular glass block of refractive index 1.5 when viewed from vertically above it, appears to be raised by 7.0 mm. Calculate the thickness of the glass slab.
A ray of light falls normally on the surface of a transparent glass slab. Draw a ray diagram to show its path and also mark angle of incidence and angle of emergence.
Fig shows a lens as a combination of a glass block and two prisms.
(i) Name the lens formed by the combination.
(ii) what is the XX' called?
(iii) Complete the ray diagram and show the path of the incident ray PQ after passing through the lens.
(iv) The final emergent ray will either meet XX' at a point or appear to come from a point on XX'. what is the point called?
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?
A glass block is having refractive index 3/2, the light ray is incident at an angle 45°. Find the sine of the angle of, refraction inside the glass block.
