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CBSE Class 12-science Answered

The image formed of an object, placed 20 cm from a concave mirror, is four times the size of the image formed of the same object when placed 45 cm from the mirror. In both cases, the image formed was real. What is the focal length of the mirror?
Asked by Topperlearning User | 20 May, 2014, 12:53: PM
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Answered by | 20 May, 2014, 02:53: PM

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CBSE 12-science - Physics
a thin stick of length f/5 is placed along principle axis of a concave mirror of focal length f such that it's image which is real and elongated just touches the stick .what is the magnification
Asked by amishavasave56.12dgatl | 27 Aug, 2021, 05:25: PM
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CBSE 12-science - Physics
Sign convention in concave mirror
Asked by raushankumarmushkipur | 02 Apr, 2021, 10:08: AM
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CBSE 12-science - Physics
When a person is moving with a constant speed the speed of his/her image appears to increase substantially as he/she moves closer to the mirror as noticed by a person sitting in a stationary car. Why? 
Asked by prakriti12oct | 11 Feb, 2020, 02:48: PM
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CBSE 12-science - Physics
Use the mirror equation to deduce that The virtual image produced by a convex mirror is always diminished in size.  
Asked by prakriti12oct | 27 Jun, 2019, 02:20: AM
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CBSE 12-science - Physics
Derive mirror formula for concex mirror.
Asked by polyrelation | 15 Mar, 2019, 04:42: PM
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CBSE 12-science - Physics
A convex mirror of radius of curvature 70 cm and a plane mirror are placed facing each other. The distance between them is 28 cm.  A point object is put midway between them on the principle axis of the mirror. Two images of the object are seen in the plane mirror. Find their distances from the plane mirror. 
Asked by mridulabarua05 | 11 Feb, 2019, 01:10: PM
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CBSE 12-science - Physics
1. The interior of a hollow metal sphere is polished to serve as a mirror. At a point 12cm from the centre of the sphere of radius 24 cm, a point source of light is placed. Locate its image formed by two successive reflections, the first reflection taking place at the  (a) far wall (b) near wall.  2. And image produced by a concave mirror is one fourth the size of the object.  If the object is moved 10 cm towards the mirror, its image will be only half the size of the object. Calculate the focal length of the mirror. 
Asked by mridulabarua05 | 07 Feb, 2019, 09:10: AM
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CBSE 12-science - Physics
A point luminous source P is placed on the principle axis of a concave mirror of radius of radius of curvature 1m at a distance of 75 cm from its pole. At what distance from the concave mirror should a plane mirror be set so that the rays from P, after reflection from the concave mirror and then from the plane mirror again converge at the point P? Does the point of convergence of the rays change if they are first reflected at the plane mirror and then at the concave mirror?
Asked by mridulabarua05 | 02 Feb, 2019, 11:23: AM
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CBSE 12-science - Physics
derive mirror formula  
Asked by Aadeshveersingh03 | 07 Jan, 2019, 07:57: AM
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CBSE 12-science - Physics
sign convention in ray optics  
Asked by mkiruthiga90 | 14 Dec, 2018, 07:32: PM
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