Ray Optics — Medium JEE physics MCQ
**[JEE Mains 2026]** A convex lens of focal length 10 cm and a concave lens of focal length 20 cm are placed in contact. An object is placed 30 cm from the combination. What is the position of the final image?
- A. 60 cm on the same side as the object
- B. 60 cm on the opposite side of the object
- C. 40 cm on the opposite side of the object
- D. 40 cm on the same side as the object
Solution
Combined focal length: 1/f = 1/10 - 1/20 = 1/20, so f = 20 cm.
Using lens formula: 1/v - 1/(-30) = 1/20.
1/v = 1/20 - 1/30 = 1/60.
v = 60 cm (positive, so on the opposite side).