Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 12

# An Object is to Be Seen Through a Simple Microscope of Focal Length 12 Cm. - Physics

An object is to be seen through a simple microscope of focal length 12 cm. Where should the object be placed so as to produce maximum angular magnification? The least distance for clear vision is 25 cm.

#### Solution

For the simple microscope, we have:
Focal length, f = 12 cm
Least distance of clear vision, d = 25 cm
For maximum angular magnification,
Image distance = Least distance of clear vision
v = d = − 25 cm

The lens formula is given by

1/v -1/u =1/f

=> 1/u =1/v -1/f

On substituting the values, we get:

1/u =1/-25 - 1/12

1/u =-(25+12)/300 = -37/300

=> u = -300/37 =-8.1  text/"cm"

So, to produce maximum angular magnification, the object should be placed 8.1 cm away from the lens.

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#### APPEARS IN

HC Verma Class 11, 12 Concepts of Physics 1
Chapter 19 Optical Instruments
Q 2 | Page 432