An equiconvex lens has power P. It is cut into two symmetrical halves by a plane containing the principal axis. The power of one part will be:
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Question

An equiconvex lens has power P. It is cut into two symmetrical halves by a plane containing the principal axis. The power of one part will be:

G1 Physics · Accepted Answer

Step 1: Cutting a lens by a plane through its principal axis decreases aperture but does not change the surface curvatures. Step 2: The lens-maker formula P = (μ − 1)(1/R₁ − 1/R₂) has no aperture term. Step 3: Thus each half retains the same focal length and power. Final answer: (D) P.