344
CHAPTER 25
25.11
His lens must form an upright, virtual image of a very distant object (
p
≈ ∞
80.0 c
) at his far
point, 80.0 cm in front of the eye. Therefore, the focal length is
m
fq
=
=−
.
If this lens is to form a virtual image at his near point (
18.0
q
cm
), the object distance
must be
( )( )
()
18.0 cm
80.0 cm
23.2 cm
18.0 cm
80.0 cm
qf
p
qf
−−
==
=
−
−
25.12
(a) The lens should form an upright, virtual image at the near point
( )
100 cm
q
when the object distance is
25.0 cm
p
=
. Therefore,
( )
25.0 cm
cm
25.0 cm
pq
f
pq
−
+−
100 cm
33.3
100 cm
=
(b) The power is
11
3.00 diopters
This is the end of the preview. Sign up
to
access the rest of the document.
This document was uploaded on 10/20/2011.
 Spring '09
 Physics, Work

Click to edit the document details