Question

Given a convex lens with focal length 25/11 cm. At what distance should the object be placed to get the image, 2.5 cm on the other side of the lens?

Answer 1

Answer:

Given: The lens of a simple magnifier has a focal length of 2.5 cm.

To find the angular magnification produced when (a) the image is at least distance of distinct vision, and (b) infinity.

Solution:

The simple magnifier achieves angular magnification by permitting the placement of the object closer to the eye than the eye could normally focus.

The angular magnification if the object is positioned such that the image is at least distant vision is given by the relationships below

M

α

=

f

25

+1=

2.5

25

+1=11

The angular magnification if the object is positioned such that the image is at infinity is given by the relationships below

M

α

=

f

25

=

2.5

25

=10