Jennifer Nguyen
PHYS100B Lab Section 08
February 5, 2021
Laboratory #1: Thin Lens Lab Report
Abstract
The purpose of this lab is to demonstrate the imaging properties of thin lenses. Using an
interactive virtual simulation of convex and concave lenses, we were able to examine the
relationships between object height, object distance, image distance, and focal length to properly
determine how projected images are operated in a lens system. In order to record the data, we
adjusted the object height, object distance, and image distance in the online simulation to
calculate the focal length (
f
) and magnification (
M
) of the concave and convex lens, which can
be found through the equations
+
and

/
, respectively. We measured the
p
1
q
1
=
f
1
M
=
p
q
M
=
h
i
h
o
focal length of a convex and concave lens through two sets of measurements of
p
, also
symbolized by
d
o
in this lab, and the image distance
d
i
, synonymous with
q
in the lab. In
addition, we applied these concepts by combining the convex and concave lenses to act as a
single lens with a focal length represented by
f
eq
. We then used the known object length and
image length of the combined lens’ focal length to determine the focal lengths of the individual
concave and convex lens through the formula
+
.
1
f
1
1
f
2
=
1
f
eq
Introduction
To complete this experiment, we require knowledge regarding the different properties
and image projection qualities of thin lenses. First, a point on an object emits light rays in a
multitude of directions, and when some of these rays pass through a lens, they create an image.
The focal point of the lens is the single point on a principal axis where the rays converge after
emerging from the lens. The distance between the focal point and the lens is the focal length,
which is symbolized by
f
. A convex lens is a type of converging lens, meaning that it causes
incident parallel rays to converge at the focal point to create a focused image, resulting in
a
positive focal length
f
. A concave lens, on the other hand, is a diverging lens, therefore causing
incident parallel rays to spread out after exiting the lens and by convention, has a negative focal
length
f
.
The thin lens equation and magnification equation are also supplementary in applying
Snell’s law of refraction. The thin lens equation takes into account the object distance
d
o
,
symbolized by
p
in this lab, and the image distance
d
i
, synonymous with
q
in the lab, to
determine the focal length
f
of the lengths through the equation
+
. Magnification also
p
1
q
1
=
f
1
relates to the distances
d
o
and
d
i
of the object and is defined as the ratio of the height of the image
to the height of the object. Magnification can be expressed through both equations
and
M
=
h
i
h
o

. If the image is inverted,
M
is negative, and when the image is upright,
M
is positive.
M
=
p
q
In addition, when a convex lens and a concave are placed together, the combined lens act
as a singular lens. As a result, the thin lens equation that takes both lenses into account is
+
, in which
f
eq
represents the focal length of the combined lens. The