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KCET2012PhysicsRay Optics

Two thin plano-convex lenses each of focal length f are placed as shown in the figure. The ratio of their effective focal lengths in the three cases is

Options

  1. A3: 2: 1
  2. B1: 2: 3
  3. C1: 2: 1
  4. D1: 1: 1

Correct answer

D. 1: 1: 1

Step-by-step solution

Effective focal length in each case is given by 1 F = 1 f + 1 f or F= f 2

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