A small telescope has an objective of focal length 140 cm and an eye piece of focal length 5.0 cm. The magnifying power of telescope for viewing a distant object is :
Correct Answer :
28
Solution :
The magnifying power (angular magnification) M of an astronomical telescope used for viewing distant objects is given by the ratio of the focal length of the objective lens (Fₒ) to the focal length of the eyepiece (F_e):
Here the objective has a focal length of 140 cm and the eyepiece has a focal length of 5.0 cm. Substituting these values:
= 28
Therefore, the telescope’s magnifying power for a distant object is 28×.
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