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MHT CET20242 May 2024Evening ShiftPhysicsRay OpticsActual

The focal length of combination of lenses formed with lenses having power of +2.50 D and -3.75 D , will be

Options

  1. A-20 cm
  2. B-40 cm
  3. C-60 cm
  4. D-80 cm

Correct answer

D. -80 cm

Step-by-step solution

aligned & P=P₁+P₂ & =2.50+(-3.75) & =2.50-3.75 & =-1.25 D & f = 1 P = 1 -1.25 =-0.8 ~m & f =-80 ~cm aligned

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