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Draw a ray diagram depicting the formation of the image by an astronomical telescope in normal adjustment.
Concept: Optical Instruments >> Telescope
You are given the following three lenses. Which two lenses will you use as an eyepiece and as an objective to construct an astronomical telescope ? Give reason
| Lenses | Power (D) | Aperture (cm) |
| L1 | 3 | 8 |
| L2 | 6 | 1 |
| L3 | 10 | 1 |
Concept: Optical Instruments >> Telescope
Show with the help of a diagram, how unpolarised light from Sun gets linearly polarised by scattering.
Concept: Some Natural Phenomena Due to Sunlight
You are given three lenses of power 0.5 D, 4 D, and 10 D to design a telescope.
1) Which lenses should be used as objective and eyepiece? Justify your answer.
2) Why is the aperture of the objective preferred to be large?
Concept: Optical Instruments >> Telescope
Does the magnifying power of a microscope depend on the colour of the light used? Justify your answer.
Concept: Optical Instruments >> Simple Microscope or a Reading Glass
Use the mirror equation to show that an object placed between f and 2f of a concave mirror forms an image beyond 2f.
Concept: Ray Optics - Mirror Formula
Write two points of difference between the phenomena of interference and diffraction.
Concept: Some Natural Phenomena Due to Sunlight
Draw the ray diagram showing refraction of light through a glass prism and hence obtain the relation between the refractive index μ of the prism, angle of prism and angle of minimum deviation.
Concept: Dispersion by a Prism
Describe an activity to show that the colours of white light splitted by a glass prism can be recombined to get white light by another identical glass prism. Also, draw a ray diagram to show the recombination of the spectrum of white light.
Concept: Dispersion by a Prism
In the following diagram, an object 'O' is placed 15 cm in front of a convex lens L1 of focal length 20 cm and the final image is formed at I at a distance of 80 cm from the second lens L2. Find the focal length of the lens L2.
Concept: Thin Lens Formula
Why does the Sun look reddish at sunset or sunrise ?
Concept: Some Natural Phenomena Due to Sunlight
An equiconvex lens of focal length 'f' is cut into two identical plane convex lenses. How will the power of each part be related to the focal length of the original lens ?
Concept: Refraction at a Spherical Surface and Lenses >> Refraction by a Lens
A double convex lens of + 5 D is made of glass of refractive index 1.55 with both faces of equal radii of curvature. Find the value of its radius of curvature.
Concept: Refraction at a Spherical Surface and Lenses >> Refraction by a Lens
Draw a ray diagram showing the image formation of a distant object by a refracting telescope ?
Concept: Optical Instruments >> Telescope
Write the two important factors considered to increase the magnifying power?
Concept: Optical Instruments >> Telescope
Describe briefly the two main limitations and explain how far these can be minimized in a reflecting telescope ?
Concept: Optical Instruments >> Telescope
Draw a ray diagram showing image formation in a compound microscope ?
Concept: Optical Instruments >> Simple Microscope or a Reading Glass
Define the term 'limit of resolution'?
Concept: Ray Optics - Mirror Formula
How is 'limit of resolution' related to resolving power of a microscope ?
Concept: Optical Instruments >> Simple Microscope or a Reading Glass
Suggest two ways by which the resolving power of a microscope can be increased?
Concept: Optical Instruments >> Simple Microscope or a Reading Glass
