The size of the image of an object, which is at infinity, as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image
(a) 1.25 cm (b) 2.5 cm
(c) 1.05 cm (d) 2 cm
(b) Convex lens will form image at it’s focus which acts like a virtual object for concave lens.
Hence for concave lens , .
So by lens formula i.e. distance of final image from concave lens by using