A point object is placed on the principal axis of a convex lens (f = 15 cm) at a distance of 30 cm from it. A glass plate (μ = 1.50) of thickness 1 cm is placed on the other side of the lens perpendicular to the axis. Locate the image of the point object.

focal length of the convex lens = 15cm

Distance of object from the lens, u = -30cm

By using lens formula,

The image is formed at 30 cm of right side due to lens only. Again, shift due to glass slab is,

The image will be formed at 30 + 0.33 = 30.33 cm from the lens on right side.