Power of Lens — Predicted 2026

AI-Predicted Question Angles for UPSC 2026

Based on trend analysis, current affairs, and recurring themes in Power of Lens.

Combination of three lenses in contact

high

While two-lens combinations are common, NEET could extend this to three lenses to test the student's consistency in applying the algebraic sum rule $P_{eq} = P_1 + P_2 + P_3$. This adds a slight computational load and increases the chance of a sign error, making it a good differentiator. The underlying principle remains the same, but it requires careful execution.

Power of a lens in a different medium (conceptual)

medium

This angle tests a deeper understanding of the Lens Maker's Formula and how focal length (and thus power) depends on the refractive indices of both the lens material and the surrounding medium. A question might ask how the power of a convex lens changes (e.g., becomes less converging, or even diverging) when immersed in a liquid with a higher refractive index than the lens itself. This moves beyond simple $P=1/f$ calculation.

Relating power to the far point/near point for vision correction

high

This is a classic application-based problem. For myopia, the far point is finite, and the corrective lens must form an image of an object at infinity at the person's far point. For hypermetropia, the near point is further than normal, and the corrective lens must form an image of an object at the normal near point (25 cm) at the person's actual near point. These problems require calculating the focal length (and thus power) needed based on the given vision defect parameters. This combines the lens formula with the power concept.