Question
Question: If the tube length of telescope is 105 cm and magnifying power is 20 for normal setting, focal lengt...
If the tube length of telescope is 105 cm and magnifying power is 20 for normal setting, focal length of objective lens is –
A
100 cm
B
10 cm
C
20 cm
D
25 cm
Answer
100 cm
Explanation
Solution
fo + fe = 105, 
= 20
solving the 2 equations
fo = 100 cm