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The optical length of an astronomical te...

The optical length of an astronomical telescope with magnifying power of ten for normal vision is `44 cm`. What is the focal length of the objective ?

A

440 cm

B

44 cm

C

40 cm

D

4 cm

Text Solution

Verified by Experts

The correct Answer is:
C
`m = (f_0)/(f_e) = 10, f_0 = 10 f_e, L = f_0 + f_e`
`44 = 10 f_e + f_e = 11 f_e`,
`f_e = 4 cm, f_0 = 10 f_e = 10 xx 4 = 40 cm`.
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