Lens sequence for ray manipulation in optics experiment

Steps:

• Ray box produces parallel light rays entering the first lens.
• Converging lens at position 1 focuses parallel rays to a real focal point beyond it.
• Converging lens at position 2, positioned at the focal length from the first focus, recollimates the rays back to parallel.
• Diverging lens at position 3 spreads the parallel rays outward, creating a diverging beam.

Why B is correct:

• Converging lenses converge parallel rays (per lens formula, f > 0 for real focus), while diverging spreads them (f < 0 for virtual focus), matching the observed sequential convergence, collimation, and divergence in ray-box setups.

Why the others are wrong:

• A: All converging lenses would repeatedly focus rays without final divergence.
• C: Initial diverging lens spreads rays early, preventing subsequent tight focusing.
• D: Initial diverging lenses broaden rays, making later convergence ineffective.

Final answer: B