A converging lens forms a real and inverted image of an object at a distance of 100 cm from it. Where should an object be placed in front of the lens, so that the size of the image is twice the size of the object? Also, calculate the power of a lens.
Given v = 100 cm, v/u = 2
Using the relation 1/f = 1/v - 1/u, we have
1/f = 1/100 - 1/-50 = 3/100
Therefore, f = 100/3 cm = 1/3 m
Hence, P = 1/f = 1/1/3 = 3D