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BITSAT2024PhysicsRay OpticsActual

In normal adjustment, for a refracting telescope, the distance between objective and eye piece is 30 cm . The focal length of the objective, when the angular magnification of the telescope is 2 , will be:

Options

  1. A20 cm
  2. B30 cm
  3. C10 cm
  4. D15 cm

Correct answer

A. 20 cm

Step-by-step solution

f ₀+ f _ e =30 And magnification, m = f ₀ f _e 2= f ₀ f _ e f ₀=2 f _ e f ₀+ f ₀ 2 =30 f ₀=20cm

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