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Sahay Sir > Question Answers > NCERT Exemplar Class 12 > Physics > Chapter 9 - Ray Optics and Optical Instruments > A small telescope has an objective lens of focal length 140cm and eye piece of focal length 5.0cm. What is the magnifying power of telescope for viewing distant objects when (a) the telescope is in normal adjustment (i.e. when the image is at infinity) (b) the final image is formed at the least distance of distinct vision (25cm).

A small telescope has an objective lens of focal length 140cm and eye piece of focal length 5.0cm. What is the magnifying power of telescope for viewing distant objects when (a) the telescope is in normal adjustment (i.e. when the image is at infinity) (b) the final image is formed at the least distance of distinct vision (25cm).

A screen is placed 90 cm from an object. The image an object on the screen is formed by a convex lens two different locations separated by 20 cm. Determine the focal length of the lens is