1.

The focal lengths of the lenses of an astronomical telescope are `50cm` and `5cm`. The length of the telescope when the image is formed at the least distance of distinct vision isA. `45 cm`B. `55 cm`C. `(275)/(6)cm`D. `(325)/(6)cm`

Answer» Correct Answer - D
Length of the telescope when final image is formed at least distance of distinct vision is
`L=f_(o)+u_(e)=f_(o)+(f_(e)D)/(f_(e)+D)=50+(2xx25)/(5+25)=(325)/(6)cm`


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