Chapter-9|Ray Optics and Optical Instrument|NCERT 12th Physics:
Combination of Thin Lenses in Contact:
Let two lenses A and B of focal lengths f₁ and f₂ placed in contact with each other. An object is placed at a point O beyond the focus of the first lens A. The first lens produces an image at I’ (virtual image), which serves as a virtual object for the second lens B, producing the final image at I.
Since, the lenses are thin, So we can assume the optical centre as P.