A small object A is placed on the principal axis of an equiconvex lens at a distance of
30 cm. The refractive index of the glass of the lens is 1.5 and its surfaces have radius of curvature,
R=20 cm. Two glass slabs
S1 and
S2 have been placed behind the lens as shown. Thickness of the two slabs are
6 cm and
4 cm respectively & refractive indices are
32 and 2 respectively.