A physics student places an object 6.0 cm
from a converging lens of focal length 9.0 cm.
What is the magnitude of the magnification
of the image produced?
1.

M

= 0
.
6
hatch (heh595) – reflection refraction imaging HW – yeazell – (55740)
9
The magnitude of the magnification is thus

M

=
vextendsingle
vextendsingle
vextendsingle
vextendsingle
q
p
vextendsingle
vextendsingle
vextendsingle
vextendsingle
=
18
.
0 cm
6
.
0 cm
= 3
.
0
.
027
10.0 points
An ordinary magnifying glass produces an
image which is
1.
real and inverted
2.
none of these
3.
virtual and inverted
4.
real and erect
5.
virtual and erect
correct
Explanation:
A magnifying glass is a double convex lens.
The object is located just inside the focal
length. Thus the image is virtual, erect, and
the magnification is larger than 1.
028 (part 1 of 3) 10.0 points
A diverging lens has a focal length of 15
.
8 cm.
2
f
2
f
f
f
Locate the image for object distance of
35
.
9 cm .
=

7
.
87492 cm
.
The magnification is
M
=

q
p
=


7
.
87492 cm
15
.
7 cm
= 0
.
501587
.
The
image
is
virtual,
upright
and
7
.
87492 cm in front of the lens.
f
q
=
fp
p

f
=

(15
.
8 cm) (35
.
9 cm)
35
.
9 cm

(

15
.
8 cm)
=

10
.
9714 cm
.
The magnification is
M
=

q
p
=


10
.
9714 cm
35
.
9 cm
= 0
.
305609
.
The
image
is
virtual,
upright
and
10
.
9714 cm in front of the lens.
029 (part 2 of 3) 10.0 points
Find the image distance for an object distance
of 15
.
7 cm
.
Correct answer:

7
.
87492 cm.
Explanation:
Let :
p
= 15
.
7 cm
.
q
=

(15
.
8 cm) 15
.
7 cm
15
.
7 cm

(

15
.
8 cm)
hatch (heh595) – reflection refraction imaging HW – yeazell – (55740)
10
The magnification is
M
=

q
p
=


5
.
35481 cm
8
.
1 cm
= 0
.
661088
.
The
image
is
virtual,
upright
and
5
.
35481 cm in front of the lens.
031 (part 1 of 4) 10.0 points
An object is placed 10 m before a convex
lens with focal length 6
.
4 m
.
Another convex
lens is placed 29
.
8 m behind the first lens with
a focal length 5
.
9 m (see the figure below).
Note:
Make a ray diagram sketch in order
to check your numerical answer.
Explanation:
Basic Concept: