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CUET · PHYSICS · PYQ PAPER 2023

Four lenses of focal length ±5 cm and ±200 cm are available for making a telescope. To produce the largest magnification for making a telescope with the help of these lenses, the focal length of eye piece should be :

  1. A + 200 cm
  2. B -5 cm
  3. C -200 cm
  4. D +5 cm
Verified Solution

Answer & Solution

Correct Answer

(D) +5 cm

Step-by-step Solution

Detailed explanation

For largest magnification, \( |M| = \frac{|f_o|}{|f_e|} \) should be maximized. Choose largest \( |f_o| = 200 \text{ cm} \). Choose smallest \( |f_e| = 5 \text{ cm} \). For an astronomical telescope, the eyepiece is a converging lens. \(f_e = +5 \text{ cm}\)