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Question : 21
Total: 30
Why is Tyndall effect shown by colloidal particles? State four instances of observing the Tyndall effect.
OR
Differentiate between a glass slab and a glass prism. What happens when a narrow beam of (i) a monochromatic light, and (ii) white light passes through (a) glass slab and (b) glass prism?
OR
Differentiate between a glass slab and a glass prism. What happens when a narrow beam of (i) a monochromatic light, and (ii) white light passes through (a) glass slab and (b) glass prism?
Solution:
The Tyndall effect is the scattering of light as a light beam passes through a colloid. The individual suspension particles scatter and reflect light, making the beam visible.
(i) The visible beam of headlights in fog is caused by the Tyndall effect. The water droplets scatter the light, making the headlight beams visible.
(ii) The Tyndall effect is used in commercial and lab settings to determine the particle size of aerosols.
(iii) Opalescent glass displays the Tyndall effect. The glass appears blue, yet the light that shines through it appears orange.
(iv) Blue eye colour is from Tyndall scattering through the translucent layer over the eye's iris.
OR
Differentiate between a glass slab and a glass prism
(i) (a) When a narrow beam of monochromaticlight passes through a glass slab, it get refracted and displaced from its original path.
(b) When a narrow beam of monochromatic light passes through a glass prism, it get refracted and deviates from its original path.
(ii) (a) When a narrow beam of white light passes through a glass slab, refraction occurs at the first face and light get dispersed into its constituent colours. When the constituent colours strike the second face, they recombine and emerges out as a white light.
(b) When a narrow beam of white light passes through a glass prism, it gets refracted and split into its constituent colours.
(i) The visible beam of headlights in fog is caused by the Tyndall effect. The water droplets scatter the light, making the headlight beams visible.
(ii) The Tyndall effect is used in commercial and lab settings to determine the particle size of aerosols.
(iii) Opalescent glass displays the Tyndall effect. The glass appears blue, yet the light that shines through it appears orange.
(iv) Blue eye colour is from Tyndall scattering through the translucent layer over the eye's iris.
OR
Differentiate between a glass slab and a glass prism
| Glass slab | Glass prism |
|---|---|
| Emergent ray is parallel to the incident ray. | Emergent ray bends at an angle to the direction of incident ray. |
| The ratio of | As the angle of incidence is increased, the angle of deviation first decreases passing through minimum and then increases. |
(b) When a narrow beam of monochromatic light passes through a glass prism, it get refracted and deviates from its original path.
(ii) (a) When a narrow beam of white light passes through a glass slab, refraction occurs at the first face and light get dispersed into its constituent colours. When the constituent colours strike the second face, they recombine and emerges out as a white light.
(b) When a narrow beam of white light passes through a glass prism, it gets refracted and split into its constituent colours.
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