An astronomical telescope in normal adjustment has an objective of focal length 100 cm and an eyepiece of focal length 5 cm. Its angular magnification is
A{'text': '100', 'label': 'A'}
B{'text': '5', 'label': 'B'}
C{'text': '20', 'label': 'C'}
D{'text': '500', 'label': 'D'}
Answer & Solution
Correct answer: C. {'text': '20', 'label': 'C'}
1. Normal adjustment: image at infinity, m = f_o / f_e.
2. m = 100 / 5 = 20.
3. (D) confuses m with f_o × f_e.
_Source: NCERT Class 12 Physics Part II, Ch 9 §9.7.2_
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