Radius of Curvature
Lab Report
Daniela Marinelli
Emily Shorrock
Emmett Keyserlingk
William MacDaddy
Purpose

To determine the
principal
characteristics of a
convex mirror & to
find the mathematical
relationship between
the radius of curvature
and the focal length of
the mirror.
Materials





Paper
Pencil
Ruler
Ray Box (5 slit)
Convex mirror
Procedure – Finding Focal Point


Shine 5 parallel light rays at the convex
mirror. Using a ruler, trace the incident and
reflected rays.
Back-trace the reflected rays – the point
where they meet is the mirror’s focal point.
f
Procedure – Finding Focal Point
Procedure – Finding Centre of Curvature



Draw the full circle of the mirror.
Measure along the principal axis to find the
exact centre of the circle – this is the
mirror’s centre of curvature.
Measure the distance from the centre of
curvature to the mirror – this is your radius
of curvature.
Procedure – Finding Centre of Curvature

Compare your results. What do you
notice about the focal length and the
radius of curvature?
?
Procedure – Characteristics of a
convex mirror

Using ray diagrams, experiment with
different object distances and observe
what images they form. Are they
upright, inverted, virtual or real?
Analysis

Images produced by convex mirrors
have multiple characteristics. In a
convex mirror, the image will be
virtual, upright, reduced in size (i.e.,
smaller than the object), and will be
located behind the mirror.
Analysis


A convex mirror is also known as a
diverging mirror. This is due to the
way incident light rays coming from
the same point diverge.
Convex mirrors are sometimes used as
surveillance devices in convenience
stores and other places which are
weary of criminals
Conclusion



In an example conducted in the results
section, it is clearly shown that when the
radius of curvature is 5cm, the focal length
is 2.5cm. This supports the formula that
f=1/2r.
In a convex mirror, the image will be virtual,
upright, reduced in size (i.e., smaller than
the object), and will be located behind the
mirror.
The variation in object distance affects the
image distance and size.
FIN