Question
Question: An astronomical telescope has an angular magnification of magnitude 5 for distant objects. The separ...
An astronomical telescope has an angular magnification of magnitude 5 for distant objects. The separation between the objective and the eyepiece is 36 cm. The final image is formed at infinity. The focal lengths f0 of the objective and fe of the eyepiece are –
A
45 cm and –9 cm respectively
B
50 cm and 10 cm respectively
C
7.2 cm and 5 cm respectively
D
30 cm and 6 cm respectively
Answer
30 cm and 6 cm respectively
Explanation
Solution
Magnification = 5 = 
Tube length = 36 = f0 + fe