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12th Uttar Pradesh Board
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The magnification produced by a astronomical telescope for normal adjustment is 10 and the length of the telescope is 1.1m. The magnification, when the image is formed atleast distance of distinct vision is

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Important Questions on Ray Optics and Optical Instruments

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12th Uttar Pradesh Board
IMPORTANT
Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 9 - Ray Optics and Optical Instruments>Exercise>Q 16
Two convex lenses of focal lengths 0.3 m and 0.05 m are used to make a telescope. The distance kept between the two in order to obtain an image at infinity is
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12th Uttar Pradesh Board
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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 9 - Ray Optics and Optical Instruments>Exercise>Q 17
In Huygen's eyepiece
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12th Uttar Pradesh Board
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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 9 - Ray Optics and Optical Instruments>Exercise>Q 18
An astronomical telescope has objective and eye-piece lenses of powers 0.5 D and 20 D respectively. The magnifying power of the Telescope is
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12th Uttar Pradesh Board
IMPORTANT
Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 9 - Ray Optics and Optical Instruments>Exercise>Q 19
A telescope consists of two thin lenses of focal lengths 0.3 m and 3 cm respectively. It is focused on moon which subtends on angle of 0.5° at the objective. Then, the angle subtended at the eye by the final image will be
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12th Uttar Pradesh Board
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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 9 - Ray Optics and Optical Instruments>Exercise>Q 20
In a photometer, two sources of light when placed at 30 cm and 50 cm respectively produce shadows of equal intensities. Their candle powers are in the ratio of
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12th Uttar Pradesh Board
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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 9 - Ray Optics and Optical Instruments>Exercise>Q 21
A lamp is hanging at a height of 40 cm from the centre of the table. If its height is increased y 10 cm, the illuminance of the lamp will decreased by
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12th Uttar Pradesh Board
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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 9 - Ray Optics and Optical Instruments>Exercise>Q 22

(i) A giant refracting telescope at an observatory has an objective lens of focal length 15 m. If an eyepiece of focal length 1.0 cm is used, what is the angular magnification of the telescope?

(ii) If this telescope is used to view the moon, what is the diameter of the image of the moon formed by the objective lens? The diameter of the moon is 3.48×106 m, and the radius of lunar orbit is 3.8×108 m.

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12th Uttar Pradesh Board
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Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 9 - Ray Optics and Optical Instruments>Exercise>Q 23
A card sheet divided into squares each of size 1 mm2 is being viewed at a distance of 9 cm through a magnifying glass (a converging lens of focal length 10 cm ) held close to the eye.
(a) What is the magnification produced by the lens? How much is the area of each square in the virtual image?
(b) What is the angular magnification (magnifying power) of the lens?
(c) Is the magnification in (a) equal to the magnifying power in (b)? Explain.