An object of size 7.0 cm is placed at 27 cm in front of a concave mirror of focal length 18 cm. At what distance from the mirror should a screen be placed so that a sharp focused image can be obtained? Find the size and nature of the image.


Here, Object distance, u = -27 cm (To the left side of mirror)

Image distance, v = ? (To be calculated)


Focal length, f = -18 cm (It is a concave mirror)


Height of object, h1 = 7.0 cm


And, Height of image, h2 = ? (To be calculated)


Now, For a mirror:



Image distance, v = -54 cm


Since the image distance is minus 54 cm, therefore, the screen should be placed at a distance of 54 cm in front of the concave mirror (on its left side). The nature of image obtained on the screen is real and inverted.


Also, For a mirror,



= -14.0 cm


Thus, the size of image is 14.0 cm.


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