Question
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:
BITSAT
Physics
Ray Optics
2024
BITSAT 2024 (Memory Based Paper 2)
BITSAT Physics Question (2024) — Solution
Options
- A. 20 cm
- B. 30 cm
- C. 10 cm
- D. 15 cm
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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