Ray Optics and Optical Instruments · Class 12 · CBSE · Science Physics
An astronomical telescope has an objective of focal length 100 cm and an eyepiece of focal length 5 cm. If the final image is formed at infinity, the…
Practice question from Ray Optics and Optical Instruments (Class 12 · CBSE · Science Physics), with the correct answer and a step-by-step solution.
medium · MCQ · Q-FE60ED
An astronomical telescope has an objective of focal length 100 cm and an eyepiece of focal length 5 cm. If the final image is formed at infinity, the magnifying power and length of the telescope tube respectively are:
- A.-20, 105 cmCorrect answer
- B.-20, 95 cm
- C.-5, 105 cm
- D.-100, 100 cm
Solution
For normal adjustment (image at infinity), magnifying power . The length of the tube is .
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