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A telescope using an eye piece of focal ...

A telescope using an eye piece of focal length 3 cm has a magnification 10 in normal adjustment. If the telescope is now used to view an object placed at a distance of 180 cm from the objective, the new length of the telescope is (assume final image is at infinity).

A

36 cm

B

39 cm

C

32 cm

D

33 cm

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The correct Answer is:
B
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