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(i) Draw a neat labelled ray diagram of an astronomical telescope in normal adjustment. Explain briefly its working. (ii) An astronomical telescope uses two lenses of powers 10D and ID. What is its magnifying power in normal

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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(i) Draw a neat labelled ray diagram of a compound microscope. Explain briefly its working. (ii) Why must both the objective and the eyepiece of a compound microscope have short focal

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Draw a schematic diagram of a reflecting telescope (Cassegrain). Write two important advantages that the reflecting telescope has over a refracting

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Explain with the help of a ray diagram, the working of an astronomical telescope. The magnifying power of a telescope in its normal adjustment is 20. If the length of the telescope is 105 cm in this adjustment, find the focal lengths of the two

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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(i) Draw a labelled ray diagram showing the image formation of a distant object by refracting telescope. Deduce the expression for its magnifying power when the final image is formed at infinity. (ii) The sum of focal lengths of the two lenses of a refracting telescope is 105 cm. The focal length of one lens is 20 times that of the other. Determine the total magnification of the telescope when the final image is formed at

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Define magnifying power of a telescope. Write its expression. A small telescope has an objective lens of focal length 150 cm and an eyepiece of focal length 5 cm. If this telescope is used to view a 100 m high tower 3 km away, find the height of the final image when it is formed 25 cm away from the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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How is the working of a telescope different from that of a microscope? The focal lengths of the objective and eyepiece of a microscope are 1.25 cm and 5 cm, respectively. Find the position of the object relative to the objective in order to obtain an angular magnification of 30 in normal

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Draw a ray diagram to show the working of a compound microscope. Deduce an expression for the total magnification when the final image is formed at the near point. In a compound microscope, an object is placed at a distance of 1.5 cm from the objective of focal length 1.25 cm. If the eyepiece has a focal length of 5 cm and the final image is formed at the near point. Estimate the magnifying power of the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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(i) (a) Draw a labelled ray diagram to show the formation of image in an astronomical telescope for a distant object. (b) Write the three distinct advantages of a reflecting type telescope over a refracting type telescope, (ii) A convex lens of focal length 10 cm is placed coaxially 5 cm away from a concave lens of focal length 10 cm. If an object is placed 30 cm in front of the convex lens. Find the position of the final image formed by the combined

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Draw the labelled ray diagram for the formation of image by an astronomical telescope. Derive the expression for its magnifying power in normal adjustment. Write two basic features which can distinguish between a telescope and a Compound

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Will the focal length of a lens for red light be more, same or less than that for blue

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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The near vision of an average person is 25cm. To view an object with an angular magnification of 10, what should be the power of the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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An unsymmetrical double convex thin lens forms the image of a point object on its axis. Will the position of the image change if the lens is

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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For a glass prism (μ = `sqrt3` ) the angle of minimum deviation is equal to the angle of the prism. Find the angle of the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A short object of length L is placed along the principal axis of a concave mirror away from focus. The object distance is u. If the mirror has a focal length f, what will be the length of the image? You may take L <<|v -

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A circular disc of radius ‘R’ is placed co-axially and horizontally inside an opaque hemispherical bowl of radius ‘a’ (Fig). The far edge of the disc is just visible when viewed from the edge of the bowl. The bowl is filled with transparent liquid of refractive index μ and the near edge of the disc becomes just visible. How far below the top of the bowl is the disc

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A thin convex lens of focal length 25 cm is cut into two pieces 0.5 cm above the principal axis. The top part is placed at (0,0) and an object placed at (–50 cm, 0). Find the coordinates of the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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In many experimental set-ups the source and screen are fixed at a distance say D and the lens is movable. Show that there are two positions for the lens for which an image is formed on the screen. Find the distance between these points and the ratio of the image sizes for these two

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A jar of height h is filled with a transparent liquid of refractive index μ (Fig). At the centre of the jar on the bottom surface is a dot. Find the minimum diameter of a disc, such that when placed on the top surface symmetrically about the centre, the dot is

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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A myopic adult has a far point at 0.1 m. His power of accomodation is 4 diopters. What power lenses are required to see distant

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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