A convex lens ‘A’ of focal length and a concave lens ‘B’ of focal length are kept along the same axis with a distance ‘ ’ between them. If a parallel beam of light falling on ‘A’ leaves ‘B’ as a parallel beam, then the distance ‘ ’ in cm will be:
- A
- B
- C
- D
Solution & Step-by-step Explanation
A parallel beam falling on a convex lens converges at its focus. For the beam to leave the second concave lens as a parallel beam, the point of convergence of the first lens must coincide with the virtual focus of the second lens.Distance between lenses .