A student wants her compound microscope to give a maximum magnifying power of

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

Problem

400

. The tube length is fixed at

20\,\text{cm}

and the chosen objective lens has a focal length

f_o=0.5\,\text{cm}

. Taking

D=25\,\text{cm}

, which one of the following focal lengths of the eyepiece should she select? (a)

2.5\,\text{cm}

(b)

3.57\,\text{cm}

(c)

2.8\,\text{cm}

(d)

2.55\,\text{cm}