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Question
Draw a ray diagram of a refracting astronomical telescope when final image is formed at infinity. Also write the expression for its angular magnification (magnifying power).
Solution
Magnifying power
M = `- "f"_"o"/"f"_"e" (1 + "f"_"e"/"D")`, when image is formed at D
M = `- "f"_"o"/"f"_"e"`, when image is formed at infinity.
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Useful Constants & Relations:
| 1 | Charge of a proton | e | 1.6 × 10-19 C |
| 2 | Speed of light in vacuum | c | 3 × 108 ms-1 |
| 1 u = 931 MeV | |||
