The focal length of an objective of a telescope is 3 metre and diamete – McqOptions

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1.	The focal length of an objective of a telescope is 3 metre and diameter 15 cm. Assuming for a normal eye, the diameter of the pupil is 3 mm for its complete use, the focal length of eye piece must be [MP PET 1989]
A.	6 cm
B.	6.3 cm
C.	20 cm
D.	60 cm
Answer» B. 6.3 cm

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