Q51 of 62 Page 106

The image of an object placed in front of a concave lens is formed at 10 cm. If the focal length of lens is 15cm then calculate distance of object from lens.

Given


Distance of image from concave lens = -10cm (as in case of concave lens, image is always virtual)


Focal length of concave lens = -15cm (focal length of concave lens is always negative)


Formula used


Lens Formula



Using lens formula



U = -30cm


The distance of object from the lens is 30cm


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An object is placed 60 cm away from a convex lens of focal length 30 cm. If the height of the object is 3 cm then calculate the position and nature of the image.

 49

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The focal length of a concave mirror is 30 cm, if an object is placed at a distance of 20 cm, calculate the position and nature of the image.

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Calculate the magnification of convex lens of focal length 10 cm when the image formed by lens is erect at the distance of nearest point of vision.