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Question
Why is the colour red used as a sign of danger?
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Solution
Red colour is used as a sign of danger due to its greater wavelength and lesser deviation (scattering).
RELATED QUESTIONS
On the basis of the experiment, "To trace the path of a ray of light through a rectangular glass slab", students of a class arrived at which one of the following conclusions?
(A) Angle of incidence is greater than the angle of emergence.
(B) Angle of emergence is smaller than the angle of refraction.
(C) Emergent ray is parallel to the refracted ray.
(D) Incident ray and emergent ray are parallel to each other.
Which of the following is the best experimental set-up out of the four shown for tracing the path of a ray of light passing through a rectangular glass slab ?
After tracing the path of rays of light through a glass slab for three different angles of incidence, a student measured the corresponding values angle of refraction r and angle of emergence e and recorded them in the table given below:
|
S. No. |
∠i |
∠i |
∠e |
|
I |
30° |
20° |
31° |
|
II |
40° |
25° |
40° |
|
III |
50° |
31° |
49° |
The correct observations are:
(A) I and II
(B) II and III
(C) I and III
(D) I, II and III
Light of a single colour is passed through a liquid having a piece of glass suspended in it. On changing the temperature of liquid, at a particular temperature, the glass piece is not seen.
Why is the light of a single colour used ?
How does the deviation produced by a prism depend on the wavelength of incident light?
Why does a fisherman aim at the tail of fish during spearfishing?
Name the material for which the refractive index is found to be maximum.
Draw ray of light bending towards the normal while passing from air to glass. Label your diagrams.
Observe the figure and name the ray AB, ray CD, ray GH.

