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A point object O is placed midway betwee...

A point object O is placed midway between on the common axis of two concave mirrors of equal focal length. If the final image is formed at the position of the object, the separation between two mirrors is ........ . Focal length of mirrors is f.

HINT:- A situation is depicted n the figure [ Note : A another possible situation for which object and its image coincide is when distance between mirrors is 4f ] .

A

f

B

2f

C

`3/2f`

D

`1/2f`

Text Solution

Verified by Experts

The correct Answer is:
B
It is clear from the defination of focal point that when object is placed on focal point, ray incident on mirror from object becomes parallel to axis of mirror after reflection.
`therefore` In figure position of object is O and position of image is O. must be on the focal point on axis of concave mirror. `therefore` Distance between both mirror = 2f
Note : Similarly if object and image O. are on the centre of curvature distance between mirrors = 4f.
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KUMAR PRAKASHAN-RAY OPTICS AND OPTICAL INSTRUMENTS-SECTION-D (MULTIPLE CHOICE QUESTIONS (MCQs))(MCQs FROM .DARPAN. BASED ON TEXTBOOK)
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  3. An object is placed at a distance of 25 cm on the axis of a concave mi...

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  6. For ..... mirror, height of image is always ...... than height of obje...

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  7. An object is placed at a distance 40 cm in front of concave mirror. Fo...

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  8. A convex mirror having focal length 20 cm is used as side glass in car...

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  9. In which of the following mirrors can a person not see a reflection la...

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  10. Object is placed 60 cm away from convex mirror. If magnification is 0....

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  11. Lateral magnification of an object by spherical mirror is 0.3. If foca...

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  12. Plane mirror is moving towards you at 5 cm//s. You can see your image ...

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  13. PQ type incident radiation and RS is the reflected ray. They are both ...

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  14. Focal length of concave mirror is f and ratio of heights of object to ...

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  15. If f is focal length and v is image distance for spherical mirror, the...

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  16. If f is focal length and u is object distance for spherical mirror, th...

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  17. If image obtained from concave mirror of focal length f is (1/n)^(th) ...

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  18. An image of an object obtained by a convex mirror is n times smaller t...

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  19. If real image obtained from concave mirror of focal length f is n time...

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  20. In an experiment to find focal length of a concave mirror a graph is d...

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