Dpp optical instruments students copy
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This document contains 15 multiple choice questions about optical instruments such as microscopes, telescopes, and cameras. The questions cover topics like the placement of objects and images, calculating magnification and resolving power, and the differences between refracting and reflecting telescope designs. Large reflecting telescopes are preferred over refracting designs because it is easier to support large mirrors mechanically than large lenses.
![Sanjeet Singh
10. The magnifying power of an astronomical telescope is 8 and the distance between the two lenses is 54 cm. The
focal length of eye lens and objective lens will be respectively.
(a) 6 cm & 48 cm (b) 48 cm & 6 cm (c) 8 cm & 64 cm (d) 6 cm & 60 cm
11. In a refracting astronomical telescope, the final image is
(a) real, inverted and magnified (b) real, erect and magnified
(c) virtual, erect and magnified (d) virtual, inverted and magnified
12. The resolving power of a telescope is increased, if
(a) the objective of a bigger diameter is used (b) the objective of a smaller diameter is used
(c) the objective of a higher focal length is used (d) the eyepiece of a shorter focal length is used
13. An astronomical telescope has a large aperture to
(a) reduce spherical aberration (b) have high resolution
(c) increase span of observation (d) have low dispersion
14. Two point white dots are 1 mm apart on a black paper. They are viewed by eye of pupil diameter 3 mm.
Approximately, what is the maximum distance at which these dots can be resolved by the eye? [Take, wavelength of
light= 500 nm]
(a) 5 m (b) 1 m (c) 6 m (d) 3 m
15. Statement 1: Very large size telescope are reflecting telescope instead of refracting telescopes.
Statement 2: It is easier to provide mechanical support to large size mirrors than large size lenses.
(a) Statement 1 is true, Statement 2 is false
(b) Statement 1 is false. Statement 2 is true.
(c) Statement 1 is true; statement 2 is true & is the correct explanation of Statement1
(d) Statement 1 is true; Statement 2 is true & is not the correct explanation of Statement 1](https://image.slidesharecdn.com/dppopticalinstrumentsstudentscopy-160906050611/85/Dpp-optical-instruments-students-copy-2-320.jpg)
Dpp optical instruments students copy
- 1. Sanjeet Singh Optical Instruments 1. To obtain a magnified image at the distance of distinct vision with simple microscope, where should the object be placed? (a) Away from the focus (b) At focus (c) Between the focus and the optical centre (d) None of the above 2. A telescope consists of two lenses of focal length 10 cm and 1 cm. The length of the telescope when an object is kept at a distance of 60 cm from the objective and the final image is formed at least distant of distinct vision is (a) 15.05 cm (b) 12.96 cm (c) 13.63 cm (d) 14.44 cm 3. From an aircraft flying at an altitude of 2000 m, photograph of the ground are taken from a camera whose size of the film is 18 cm x 18 cm and the focal length of the camera is 50 cm. The area of the ground that can be photographed by the camera is (a) 648900 cm2 (b) 32831 cm2 (c) 518400 m2 (d) 18000 cm2 4. A light source is placed at a distance b from a screen. The power of the lens required to obtain k- fold magnified image is (a) 1k kb (b) 2 1k kb (c) 1 kb k (d) 2 1 kb k 5. To obtain the maximum magnification with a simple microscope, where should the eye be placed? (a) Close to the lens (b) Half way between the focus and the optical centre (c) Close to the focus (d) None of the above 6. In a compound microscope, the objective produces a magnification of 10, while the eyepiece produces a magnification of 5, then the overall magnification achieved by a compound microscope is (a) 2 (b) 50 (c) 0.5 (d) 25.00 7. If 0f and ef be the focal lengths of the objective and the eyepiece of astronomical tube scope, the length of the tube is (a) 0 ef f (b) 0 ef f (c) 0 ef f (d) 0 0 e e f f f f 8. An astronomical telescope is set for normal adjustment and the distance between its objective and eyepiece is 1.05 cm. The magnifying power of the telescope is 20. What is the focal length of the objective? (a) 2 m (b) 1 m (c) 0.5 m (d) 0.25 m 9. The magnifying power of a telescope is 9. When it is adjusted for parallel rays, the distance between the objective and the eyepiece is found to be 20 cm. The focal lengths of the lenses are (a) 18 cm, 2 cm (b) 11 cm, 9 cm (c) 10 cm, 10 cm (d) 15 cm, 5 cm
- 2. Sanjeet Singh 10. The magnifying power of an astronomical telescope is 8 and the distance between the two lenses is 54 cm. The focal length of eye lens and objective lens will be respectively. (a) 6 cm & 48 cm (b) 48 cm & 6 cm (c) 8 cm & 64 cm (d) 6 cm & 60 cm 11. In a refracting astronomical telescope, the final image is (a) real, inverted and magnified (b) real, erect and magnified (c) virtual, erect and magnified (d) virtual, inverted and magnified 12. The resolving power of a telescope is increased, if (a) the objective of a bigger diameter is used (b) the objective of a smaller diameter is used (c) the objective of a higher focal length is used (d) the eyepiece of a shorter focal length is used 13. An astronomical telescope has a large aperture to (a) reduce spherical aberration (b) have high resolution (c) increase span of observation (d) have low dispersion 14. Two point white dots are 1 mm apart on a black paper. They are viewed by eye of pupil diameter 3 mm. Approximately, what is the maximum distance at which these dots can be resolved by the eye? [Take, wavelength of light= 500 nm] (a) 5 m (b) 1 m (c) 6 m (d) 3 m 15. Statement 1: Very large size telescope are reflecting telescope instead of refracting telescopes. Statement 2: It is easier to provide mechanical support to large size mirrors than large size lenses. (a) Statement 1 is true, Statement 2 is false (b) Statement 1 is false. Statement 2 is true. (c) Statement 1 is true; statement 2 is true & is the correct explanation of Statement1 (d) Statement 1 is true; Statement 2 is true & is not the correct explanation of Statement 1