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A double convex lens has power P and same radii of curvature R of both the surfaces. The radius of curvature of a surface of a plano-convex lens made of the same material with power 1.5P is

Asked in JEE Main 6th Sept 2nd Shift 2020 · Lens maker's formula and power

• (1) 2R
• (2) R/2
• (3) (3R)/2
• (4) R/3

Step-by-step solution

Why the other options are wrong

• (1) Gets the plano-convex radius for power P/2 instead of 1.5P.
• (2) Forgets the plano-convex has only one curved face.
• (3) Multiplies R by 1.5 instead of dividing.

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