JEE Main & Advanced
Physics
Ray Optics
Question Bank
Mock Test - Geometrical Optics
question_answer
A convex lens of focal length 20 cm and a concave lens of focal length\[f\]are mounted coaxially 5 cm apart. Parallel beam of light incident on the convex lens emerges from the concave lens as a parallel beam. Then, \[f\] (in cm) is