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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
Define refraction and state the laws of refraction.
A monochromatic ray of light passes from air to glass. The wavelength of light in air is λ, the speed of light in air is c and in glass is V. If the absolute refractive index of glass is 1.5, write down
- the relationship between c and V,
- the wavelength of light in glass.
In the adjacent diagram, AO is a ray of light incident on a rectangular glass slab.
- Complete the path of the ray till it emerges out of the slab.
- In the diagram, mark the angle of incidence (i) and the angle of refraction (r) at the first interface. How is the refractive index of glass related to the angles i and r?
- Mark angles of emergence by the letter e. How are the angles i and e related?
- Which two rays are parallel to each other? Name them.
- Indicate in the diagram the lateral displacement between the emergent ray and the incident ray. State one factor that affects the lateral displacement.
When light travels from a rarer to a denser medium, its speed ______.
How does the angle of minimum deviation produces by a prism change with increase in :
the refracting angle of prism?
Four students A, B, C and D traced the paths of incident ray and the emergent ray by fixing pins P and Q for incident ray and pins R and S for emergent ray for a ray of light passing through a glass slab.
The correct emergent ray was traced by the student:
(1) A
(2) B
(3) C
(4) D
The critical angle for glass-air interface is :
Express the refractive index μ of a medium in terms of the velocity of light.
Trace a ray of light incident at 30° on a surface if travelling from glass to air. What is the angle of refraction in this case? (R.I. for glass = 3/2).
What is lateral displacement?
