An astronomical telescope has an objective focal length of and initially uses an…

PHYSICS · Single correct · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments

Problem

An astronomical telescope has an objective focal length of

1.0\,\text{m}

and initially uses an eyepiece of focal length

2.5\,\text{cm}

. The eyepiece is replaced by another of focal length

2.0\,\text{cm}

while keeping the objective unchanged. Approximately how does the magnitude of the magnifying power change? (a) Increases by

20\%

(b) Increases by

25\%

20\%

(d) Increases by

12.5\%