LESSON IN MIRROR GRADE 10 SECOND QUARTER

1. NOTE: Use PRESENTER VIEW (REMOVE THIS NOTE AND THE PHOTO FROM THIS SLIDE)
SET THE SAME SETTINGS (Indicated in the RED SQUARE)
THE POWERPOINT VERSION REQUIRES TO BE 2019,
If it is lower than 2019, SOME TRANSITIONS WILL BE SET to FADE
SET THE TV VOLUME TO 25
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2. WARNING:
FLASHING LIGHTS AND SOME LOUD NOISES
AND SOME FUNNIES

5. LIGHT
Our Science book will be irrelevant. But computations
are sourced from the books.
The presentation will be 2 feet deeper than the books.

6. LIGHT
In that game, light is an important mechanic. Also in real life, we use light to see clearly. In daylight we use
the sun and its REFLECTION to the surface so LIGHT can bounce around. And in the nighttime, we use
electrical fixtures that produce light like BULBS, LAMPS and so on…
Oh, and! Vision begins with light passing through the cornea.
Now, we are going to learn about LIGHT and about REFLECTION.

7. AGENDA
Introduction
Reflection of Light in Lenses
Reflection of Light in Mirrors
Mirrors

8. Introduction
Mirrors
To understand the concept of a mirror, one must
know what is the phenomenon behind the mirror
and what makes it a reflecting material.
It is defined as a reflecting surface and can be
explained by the law of reflection, which states
that when a ray of light is made to fall on the
reflecting surface of the mirror all lie in the same
plane and the angle of incidence is equal to the
angle of reflection.
They can be plane or spherical. Spherical Mirrors
has two kinds, concave and convex mirror.

9. CONCAVE PLANE CONVEX
MIRRORS | REFLECTIONS
CONVEX CONCAVE PLANE

10. CONCAVE PLANE CONVEX
MIRRORS | REFLECTIONS
CONVEX CONCAVE PLANE

11. CONVEX
It is a curved mirror where the reflective
surface bulges out toward the light
source. The bulging-out surface reflects
light outwards and is not used to focus
light. These mirrors form a virtual image
as the focal point, and the center of
curvature are imaginary points in the
mirror that cannot be projected on a
screen as the image is inside the mirror.
The image looks smaller than the object
from a distance but gets larger as the
object gets closer to the mirror.
Example 1A

12. CONVEX
It is a curved mirror where the reflective
surface bulges out toward the light
source. The bulging-out surface reflects
light outwards and is not used to focus
light. These mirrors form a virtual image
as the focal point, and the center of
curvature are imaginary points in the
mirror that cannot be projected on a
screen as the image is inside the mirror.
The image looks smaller than the object
from a distance but gets larger as the
object gets closer to the mirror.
Example 1B

13. CONCAVE PLANE CONVEX
MIRRORS | REFLECTIONS
CONVEX CONCAVE PLANE

14. CONCAVE
Example 2A
A curved mirror where the reflective
surface is on the inner side of the curved
shape. It has a surface that curves
inward, resembling the shape of the inner
surface of a hollow sphere. These mirrors
are also converging mirrors because they
cause light rays to converge or come
together after reflection. Concave mirrors
reflect upside down because of the way
they bend light. The curved surface of the
mirror causes light rays from the top of an
object to be reflected downward and light
rays from the bottom of the object to be
reflected upward.

15. CONCAVE
Example 2B
A curved mirror where the reflective
surface is on the inner side of the curved
shape. It has a surface that curves
inward, resembling the shape of the inner
surface of a hollow sphere. These mirrors
are also converging mirrors because they
cause light rays to converge or come
together after reflection. Concave mirrors
reflect upside down because of the way
they bend light. The curved surface of the
mirror causes light rays from the top of an
object to be reflected downward and light
rays from the bottom of the object to be
reflected upward.

16. CONCAVE PLANE CONVEX
MIRRORS | REFLECTIONS
CONVEX CONCAVE PLANE

17. PLANE
Example 3B
Plane mirror is with a flat reflective
surface. It is the simplest type of mirror
and is the most common type of mirror
used in everyday life. These reflect light
rays in a straight line. This angle of
incidence is the angle between the
incoming ray of light and the normal to
the mirror surface. The normal is an
imaginary line that is perpendicular to the
mirror surface at the point where the light
ray strikes the mirror.

18. PLANE
Example 3B
Plane mirror is with a flat reflective
surface. It is the simplest type of mirror
and is the most common type of mirror
used in everyday life. These reflect light
rays in a straight line. This angle of
incidence is the angle between the
incoming ray of light and the normal to
the mirror surface. The normal is an
imaginary line that is perpendicular to the
mirror surface at the point where the light
ray strikes the mirror.

19. LET’S TALK ABOUT
SPHERICAL FRAMEWORKS
STARTING NOW… TURN TO PAGE 100

20. FRAMEWORK OF SPHERICAL MIRRORS
Spherical mirrors have several key parts, including the principal
axis, principal focus, center of curvature, radius of curvature, vertex,
and aperture. These parts are important for understanding how
spherical mirrors reflect light and form images.
The location of the center of curvature and principal focus
depends on the type of spherical mirror. For a concave mirror, the
center of curvature and principal focus are located in front of the
reflecting side. For a convex mirror, the center of curvature and
principal focus are located at the back of the reflecting side.

21. FRAMEWORK OF SPHERICAL MIRRORS
LET’S SUMMARIZE THE KEY PARTS!

22. FRAMEWORK OF SPHERICAL MIRRORS
LET’S SUMMARIZE THE KEY PARTS!
KEY PART DESCRIPTION
Principal Axis An imaginary line that passes through the spherical mirror
where principal focus and center of curvature are located.
Principal Focus (F) A point at the principal axis where all of the reflected rays
meet. The focal length (f) is the distance between the
principal focus and the vertex of the mirror.
Center of Curvature (C) A point at the principal axis that is located at the very center
of the spherical mirror.
Radius of Curvature
(R)
The distance between the center of curvature to the spherical
mirror. The focal length (f) is equal to half of the radius of
curvature.
Vertex The point of intersection between the principal axis and the
spherical mirror.
Aperture The diameter of the spherical mirror.

23. FRAMEWORK OF SPHERICAL MIRRORS
LET’S SUMMARIZE THE KEY PARTS!
LOCATION OF THE CENTER OF CURVATURE AND PRINCIPAL FOCUS
CONCAVE MIRROR: IN FRONT OF THE REFLECTING SIDE
CONVEX MIRROR: AT THE BACK OF THE REFLECTING SIDE

24. NOW
PREDICTING IMAGES FORMED BY
SPHERICAL MIRRORS USING RAYS
PAGE 100 - 101

25. We can use a simple graphical method to predict
the properties of an image formed by a spherical mirror.
This method involves tracing the paths of a few
particular rays that diverge from a point on the object
and are reflected by the mirror.
PREDICTING IMAGES FORMED BY
SPHERICAL MIRRORS USING RAYS
THERE ARE FOUR SIMPLE STEPS TO FOLLOW

26. PREDICTING IMAGES FORMED BY SPHERICAL MIRRORS USING RAYS
THERE ARE FOUR SIMPLE STEPS TO FOLLOW
1. Draw a ray of light parallel to the principal axis.
oThis ray will be reflected through the principal focus.
2. Draw a ray of light passing through the focus.
oThis ray will be reflected parallel to the principal axis.
3. Draw a ray through the center of curvature.
oThis ray will be reflected back along its own path.
4. Draw a ray meeting the mirror at the pole.
oThis raw will be reflected so as to make an equal angle with
the principal axis.

27. NOW
IMAGES FORMED BY
SPHERICAL MIRRORS
PAGE 101

28. CONCAVE AND CONVEX MIRRORS
Structure
Concave and convex mirrors differ in structure. The reflecting
side of a concave mirror is at the back of the bulge, while the
reflecting side of a convex mirror is in front of the bulge
Image Formation
Concave and convex mirrors also differ in the type of images
they form. Concave mirrors can form both real and virtual
images, depending on the distance of the object from the
mirror. Convex mirrors always form virtual images.

29. LET’S UNDERSTAND IT BETTER!
A great example is a metal spoon of how concave and convex
mirrors differ. The back of the spoon acts as a convex mirror,
while the scooping portion of the spoon acts as a concave mirror.
Convex Mirrors Concave Mirrors
Convex mirrors always form virtual
images that are erect and reduced in
size. This is why convex mirrors are
used in the side mirrors of cars. Convex
mirrors provide a wide field of view,
which is helpful for drivers to see
objects behind them.
The image formed by a concave mirror
depends on the distance of the object
from the mirror. If the object is placed
beyond the focal point of the mirror, a
real image will be formed. Real images
are inverted and can be projected onto
a screen. If the object is placed
between the focal point and the mirror,
a virtual image will be formed. Virtual
images cannot be projected onto a
screen

30. NOW
THE MIRROR EQUATION
AND MAGNIFICATON
PAGE 101 - 103

31. MIRROR EQUATION
The mirror equation is a mathematical expression that
can be used to determine the properties of an image
formed by a mirror. The equation is as follows:
1
𝑓
= 1
𝑠
+ 1
𝑠1
Where:
• f is the focal length of the mirror
• s is the object distance (distance from the object to the mirror)
• 𝑠1
is the image distance (distance from the image to the mirror)

32. MIRROR EQUATION
The mirror equation can be used to determine the following
properties of an image:
Image size: The image size is directly proportional to the object
size and inversely proportional to the distance between the
object and the mirror.
Image Type: The image type can be real or virtual. A real image
can be projected onto a screen, while a virtual image cannot.
Image Orientation: The image orientation can be upright or
inverted.

33. The following sign rules apply to the mirror equation:
• Object Distance (𝑠): Positive if the object is on the same side of
the mirror as the incoming light, negative if the object is on the
other side.
• Image Distance (𝑠1
): Positive if the image is on the same side of
the mirror as the outgoing light, negative if the image is on the
other side.
• Focal Length (𝑓): Positive for concave mirrors, negative for
convex mirrors.
SIGN RULES

34. LET’S TRY
Example 1:
• Object distance: 10cm
• Focal length: 6cm
1
𝑓
= 1
𝑠
+ 1
𝑠1
What is / are Missing?

35. LET’S TRY
Example 2:
• Object distance: 10cm
• Radius of Curvature: 12cm
1
𝑓
= 1
𝑠
+ 1
𝑠1
What is / are Missing?

36. MAGNIFICATION
Spherical mirrors can form either magnified or reduced images.
Convex mirrors always form reduced images, while concave
mirrors can form either magnified or reduced images
depending on the location.
𝑀 =
ℎ1
ℎ
=
𝑠1
𝑠
Where:
• M is the magnification
• ℎ1
is the height of the image
• h is the height of the object.
• s is the object distance (distance from the object to the mirror)
• 𝑠1
is the image distance (distance from the image to the mirror)

37. MAGNIFICATION
Using this formula, it is important to remember that all
images located above the principal axis are positive and
all heights located below the principal axis are negative
𝑀 =
ℎ1
ℎ
=
𝑠1
𝑠

38. LET’S TRY
Example 1:
• Object Height: 10cm
• Image Height: -5cm
• Object Distance: 10cm
• Image Distance: -5cm
Verify if the magnified is image reduced or enlarged
𝑀 =
ℎ1
ℎ
=
𝑠1
𝑠

39. ACTIVITY:
It is a curved mirror where the reflective surface bulges out towards the
light source.
- Convex Mirror
A point of intersection between the principal axis and the spherical mirror.
- Vertex
It is the most common type of mirror.
- Plane Mirror
The distance between the center of curvature to the spherical mirror.
- Radius of Curvature
A curved mirror where the reflective surface is on the inner side of the
curved shape.
- Concave Mirror

40. ACTIVITY:
1. It is a curved mirror where the reflective surface bulges out
towards the light source.
2. A point of intersection between the principal axis and the
spherical mirror.
3. It is the most common type of mirror.
4. The distance between the center of curvature to the spherical
mirror.
5. A curved mirror where the reflective surface is on the inner
side of the curved shape.

41. ACTIVITY:
1. Bobby places a 4.25-cm tall light bulb a
distance of 36.2 cm from a concave mirror. If
the mirror has a focal length of 19.2 cm,
then what is the image height and image
distance.