Lesson 1: Reflection of Light in Plane Mirrors Lesson 2: Reflection of Light in Spherical Mirrors Lesson 3: Optical Instruments (Camera, Microscope, Telescope) Reference: DepEd K12. (2019, July). Science Grade 10 Learner’s Materials. [PDF File]. Retrieved from https://www.depedk12.com/2019/07/science-grade-10-learners-materials-pdf.html

1. SCIENCE 10 – WEEK 3

2. UNIT 1
REFLECTION OF LIGHT IN
MIRRORS

3. UNIT MAP
Lesson 1:
Reflection of
Light in
Plane Mirrors
Lesson 2:
Reflection of
Light in
Curved
Mirrors
Lesson 3:
Optical
Instruments

4. BEFORE YOU START WITH OUR LESSON,
ANSWER FIRST THE PRE-ASSESSMENT ON
THE ASSESSMENT SHEETS.

5. LESSON 1: REFLECTION OF
LIGHT IN PLANE MIRRORS

6. OBJECTIVES:
In this lesson, you are expected to:
1. differentiate real and virtual image; and
2. compare the actual size and the distance
from the mirror of the object with that of
the image formed by plane mirror.

7. REFLECTION OF LIGHT
Reflection is the bouncing off of light rays when
it hits a surface like a plane mirror.
Real Image – formed in front of the mirror and is
always upside down relative to the object. It can
be projected on a screen placed in front of
mirror.
Virtual Image – formed behind the mirror and is
upright relative to the object and cannot be
projected on a screen.

8. REFLECTION
 The change in direction of a wave when it strikes and rebounds
from a surface or the boundary between two media
 Reflection can be thought of as light “bouncing off” a surface
(although this phenomena is much more complex).
 Regular (specular) reflection – reflection from very smooth
(mirror) surfaces
 Irregular (diffuse) reflection – reflection from relatively rough
surfaces

9. SPECULAR & DIFFUSE REFLECTION

10. LAW OF REFLECTION
The angle of reflection qr is equal to the angle of incidence qi.
The reflected and incident rays are also in the same plane.

11. REFLECTION OF LIGHT IN
PLANE MIRRORS
Images formed by plane mirrors are always
virtual, upright, the same size as the object,
the same distance behind the mirror as the
object is in front of the mirror, and laterally
reversed. Laterally reversed means that left
of the object becomes the right of the
image, and vice versa.

12. REFLECTION OF LIGHT IN
PLANE MIRRORS
Suppose that a girl, with a sitting height
of 3ft, is facing 2 ft away from a plane
mirror as she puts blush-on on her right
cheek. Describe the image formed by
each mirror.

13. REFLECTION OF LIGHT IN
PLANE MIRRORS
Explanation: We are given that the girl is 2ft
away from the mirror. Recall that images formed
by plane mirrors are always virtual, upright, the
same size as the object, the same distance
behind the mirror as the object is in front of the
mirror, and laterally reversed. So the girl will see
her image in mirror that is 2ft at its back,
meaning it is virtual. It is sitting at the same size
of 3.5ft height and the image will tell us that she
is putting blush-on on her left cheek.

14. LEARN MORE!
To learn more about our lesson, open the
file Reflection of Light and Image
Formation in your flash drive or access
this link:
http://www.physicsclassroom.com/class/
refln/Lesson-3/Reflection-of-Light-and-
Image-Formation

15. QUIZTIME!
 Let’s check your understanding of our
lesson. Answer Activity 2-3 on the
ASSESSMENT SHEETS.

16. LESSON 1: REFLECTION OF
LIGHT IN PLANE MIRRORS

17. SCIENCE 10 – WEEK 3

18. UNIT 1
REFLECTION OF LIGHT IN
MIRRORS

19. UNIT MAP
Lesson 1:
Reflection of
Light in
Plane Mirrors
Lesson 2:
Reflection of
Light in
Curved
Mirrors
Lesson 3:
Optical
Instruments

20. LESSON 2: REFLECTION OF
LIGHT IN CURVED MIRRORS

21. OBJECTIVES:
In this lesson, you are expected to:
1. describe the location, size, and
orientation of the images formed by curved
mirrors; and
2. construct ray diagrams to determine the
location, orientation, size, and type of
images formed by curved mirror.

22. KEYTERMS
 Center of Curvature, C - the center of the
sphere of which the mirror is part. Its
distance from the mirror is known as the
radius.
 Vertex,V - the center of the mirror.
 Focal Point/ Focus, F - the point between
the center of the curvature and vertex. Its
distance from the mirror is known as the
focal length, f.
 Principal Axis – the point where the
reflected rays meet (concave) or where
they seem to come from (convex).

23. TYPES OF CURVED MIRRORS
a. Convex mirrors – the image formed
by convex mirror is never real because
the reflected rays spread out from the
mirror. Images formed by convex
mirror are always found between F and
V, virtual, upright, and smaller than the
object. Example: side mirror and
security mirrors that provide wider
range of view for the driver by making
images smaller and closer than they
appear.

24. TYPES OF CURVED MIRRORS
b. Concave mirrors – a concave
mirror can produce real or virtual
images, depending on the distance
between the mirror and the object.
The image may also be larger than,
the same size as, or smaller than
the object. Example: dental mirrors
for the dentist to view an enlarged
virtual image of the teeth.

25. THE FOUR PRINCIPAL RAYS
Images formed in a curved mirror
can be located and described
through ray diagramming.The P – F
ray, F – P ray, C – C ray, and theV ray
are the ‘Four Principal Rays’ in curve
mirrors.

26. THE FOUR PRINCIPAL RAYS
1. P – F Ray. A ray of light
parallel to the principal axis is
reflected passing through the
principal focus, F.

27. THE FOUR PRINCIPAL RAYS
1. P – F Ray. A ray of light
parallel to the principal axis is
reflected as if passing through
the principal focus, F.

28. THE FOUR PRINCIPAL RAYS
2. F – P Ray. A ray of light
passing through the focus, F
is reflected parallel to the
principal axis.

29. THE FOUR PRINCIPAL RAYS
2. F – P Ray. A ray of light
directed towards the focus, F
is reflected parallel to the
principal axis.

30. THE FOUR PRINCIPAL RAYS
3. C – C Ray. A ray of light
passing through the center of
curvature, C reflects back
along its own path.

31. THE FOUR PRINCIPAL RAYS
3. C – C Ray. A ray of light
directed towards the center
of curvature, C reflects back
along its own path.

32. THE FOUR PRINCIPAL RAYS
4.V Ray. A ray of light
directed to the vertex reflects
at equal angle from the
principal axis.

33. THE FOUR PRINCIPAL RAYS
4.V Ray. A ray of light
directed to the vertex reflects
at equal angle from the
principal axis.

34. STEPS IN DETERMININGTHE
POSITION AND NATURE OF IMAGE
FORMED IN CURVED MIRRORS
1. From the object, draw the
first ray (P – F ray).

35. STEPS IN DETERMININGTHE
POSITION AND NATURE OF IMAGE
FORMED IN CURVED MIRRORS
2. From the same point on the
object, draw the second (F – P ray).

36. STEPS IN DETERMININGTHE
POSITION AND NATURE OF IMAGE
FORMED IN CURVED MIRRORS
3.Third (C – C ray).

37. STEPS IN DETERMININGTHE
POSITION AND NATURE OF IMAGE
FORMED IN CURVED MIRRORS
4. Fourth (V ray) rays.

38. STEPS IN DETERMININGTHE
POSITION AND NATURE OF IMAGE
FORMED IN CURVED MIRRORS

39. STEPS IN DETERMININGTHE
POSITION AND NATURE OF IMAGE
FORMED IN CURVED MIRRORS

40. IMAGES FORMED IN CONCAVE
MIRRORS
Location
of the
Object
Image
Location Orientation Size Type
Very far
(at
infinity)
At F inverted very small, almost
a point
real
Beyond C Between C and F inverted smaller than the
object
real
At C At C inverted same size as the
object
real
Between C
and F
Beyond C inverted bigger than the
object
real
At F At infinity No image formed because all reflected rays are parallel
Between F Back of the mirror upright bigger than the virtual

41. LEARN MORE!
To learn about our lesson open the file
MirrorTherapy on your flash drive or visit
the link
http://www.physiopedia.com/Mirror_Th
erapy

42. QUIZTIME!
 Let’s check your understanding of our
lesson. Answer Activity 4 on the
ASSESSMENT SHEETS.

43. LESSON 2: REFLECTION OF
LIGHT IN CURVED MIRRORS

44. SCIENCE 10 – WEEK 3

45. UNIT 1
REFLECTION OF LIGHT IN
MIRRORS

46. UNIT MAP
Lesson 1:
Reflection of
Light in
Plane Mirrors
Lesson 2:
Reflection of
Light in
Curved
Mirrors
Lesson 3:
Optical
Instruments

47. LESSON 3: OPTICAL
INSTRUMENTS

48. OBJECTIVE:
In this lesson, you are expected to:
1. explain how different optical
instruments work.

49. CAMERA
It is the man’s answer to the eye’s
inability to produce a permanent record
of the image formed at the retina. Roger
Bacon, an English philosopher and
scientist, was believed to have invented
the instrument in 1267. In 1826, Joseph-
Nicéphore Niépce, a French scientist and
inventor, created the first photographic
camera that has a lens to project an
image onto light-sensitive paper.

50. CONVENTIONAL CAMERA
It uses film in storing images. A
35mm conventional camera can
take only up to 36 exposures. One
has to rewind the film, open the
back, and replace film with another
if more pictures are to be taken.
The film will have to be developed
and the negatives printed before
seeing the pictures.

51. DIGITAL CAMERA
It uses digital sensor array made of millions
of tiny sensor points called pixels, which is
short for “picture elements”, that convert
light into electrical charges. They are laid out
in an array with rows and columns. For
instance, a camera with 3000 pixels
horizontally and 1000 pixels vertically has
3000 x 1000 pixels equal to 3 million pixels.
Thus, it is called 3 Megapixels camera. Digital
camera is provided with video monitor for
instant viewing of each picture taken.

52. MAGNIFIER AND MICROSCOPE
To examine an object, we hold it as near
as possible to our eye so that bigger
image can be viewed, however, if an
object is placed shorter than 25-cm from
the eye, blurred image is produced.
Magnifying glasses and microscopes
produce a virtual, upright and enlarged
image of an object.

53. TELESCOPE
A device that enables us to see distant
objects. The first image formed at
principal focus of objective is real,
inverted and smaller. Then the
eyepiece, acting like a magnifying
glass produces a magnified virtual
final image at infinity. A zoom lens is
also telescope mounted on a camera
while a binocular is simply two
telescope mounted side by side.

54. LEARN MORE!
To learn about our lesson open the file
Digital Camera or visit the link
http://electronics.howstuffworks.com/ca
meras-photography/digital/digital-
camera2.htm

55.  Let’s check your understanding of our
lesson. Answer Activity 5 on the
ASSESSMENT SHEETS.

56. VALUES INTEGRATION
Have you heard the Golden Rule of Life:
“Do unto others what you want others do
unto you”? How does this line related to
what you had learned in studying plane
mirrors? Do you believe that what you do in
life will reflect back to you also? Use the
same situations that we are experiencing or
witnessing right now in supporting your
answers.

57. “There is a spiritual mirror that we can look into
that will show us who we are.That mirror is called
THEWORD OF GOD”
James 1:22-25

58. LESSON 3: OPTICAL
INSTRUMENTS