Question

we are given a convex lens of focal length 20cm .draw ray diagram to show the nature, size and position of the image formed when the object is kept at a distance of 35 cm from the lens (for drawing ray diagram using appropriate scale.)

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Answer 1

Explanation :

Given :

Focal length = -20cm (f)

Object distance = -35cm (u)

Image distance = ? (v)

By lens formula ,

1/v - 1/u = 1/f

1/v - 1/-35 = 1/-20

1/v = 1/-20 + 1/35

1/v = 7-4/140

1/v = 3/140

v = 140/3cm

v = 46.67cm

Hence,

Nature of image is real and inverted

Image is enlarged

Image is formed 46.67cm from optical center on right side