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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).
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
Light passes through a rectangular glass slab and through a triangular glass prism. In what way does the direction of the two emergent beams differ and why?
How is the refractive index of a medium related to the speed of light in it?
How does the angle of deviation produced by a prism change with increase in the angle of incidence. Draw a curve showing the variation in the angle of deviation with the angle of incidence at a prism surface.
Fill in the blanks to complete the following sentence
When light travels from a denser to a rarer medium, its speed ……………….
Select from the following the best experimental set-up for tracing the path of a ray of light through a glass slab:
(A) I
(B) II
(C) III
(D) IV
Does the depth of a tank of water appear to change or remain the same when viewed normally from above?
During sunset and sunrise, the sun is seen when it is slightly below the horizon. Give reason.
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?
Calculate the velocity of light in a glass block of refractive index 1.5. (Velocity of light in air = 3 × 108 m/s)
