Download images in plane mirrors

Name: _________________________________________
Date: ______________________
WHAT IS LIGHT?
Read pages 463 – 465
Light is an
_________________
wave. Electromagnetic waves do not require a medium
for transmission. Instead, light energy is transferred through
A
____________
_________________.
is a physical substance through which energy can be transferred.
Examples include air that sound and heat can transfer through or copper wire that electricity can
pass through.
_________
is a method of energy transmission that does not require a medium.
An electromagnetic wave is a wave with both
___________________________
parts that does not require a medium to transmit. In a vacuum the wave travels at the speed of
light, 3.00 x 108 m/s. Electromagnetic wave types include radio waves, microwaves, visible light, xrays and gamma rays.
The
_____________________
is the classification of waves by their energy levels.
Visible light is a small range of the entire spectrum.
__________________ consists of electromagnetic waves that the human eye detects.
________________ is made up of all the colours of light in the visible spectrum.
Recall
that light colours are red, orange, yellow, green, blue, indigo and violet, and all the shades in
between.
Lesson 1 - Light and Light Production
Physics: Optics Unit
Page 1 of 3
Name: _________________________________________
Date: ______________________
HOW IS LIGHT PRODUCED?
Read pages 470 – 476
Light is produced from
___________ sources such as the sun, incandescent, electric
discharge, fluorescence , phosphorescence, chemiluminescence, bioluminescence,
triboluminescence, light-emitting diodes and lasers. The eye is able to see all other objects due to
the light being
__________ from them to the eye.
Incandescence
When materials such as metals are heated to
_________________, they begin to glow.
Initially the glowing colour will be red, and as the object gets hotter, the colour will transition from
red to orange, yellow, white and then bluish white. The process of producing light by heating a
material to a high temperature is called
__________________.
Examples:

Glowing burner on a stove top

Incandescent light bulb

Flame from a candle
Electric Discharge
When an electrical current
___________________, light is produced.
Lightning and
neon are some examples.
Phosphorescence
Phosphors
____________________ at high energy and release visible light at lower
energy. The light is released
__________.
We see this process in “glow in the dark”
objects.
Fluorescence
When an object absorbs ultraviolet light and
_____________ releases the energy as
visible light, it is known as fluorescence. Fluorescent light bulbs and highlighters are examples of
this.
Lesson 1 - Light and Light Production
Physics: Optics Unit
Page 2 of 3
Name: _________________________________________
Date: ______________________
Chemiluminescence
A
_________________
can result in the production of light (energy). Typically no heat
is produced in this type of reaction. Light sticks are an example of this type of light.
Bioluminescence
Chemiluminescence occurring in a ________ such as a firefly is known as bioluminescence.
Triboluminescence
When certain types of
________________ are scraped or banged together, sparks are
produced.
Light-Emitting Diodes (LED)
A diode is a type of
____________________
made from semi-conductor materials
such as silicon. A diode only allows current to flow in one direction. In an LED,
_____________,
light is emitted.
Homework:
1. Using Table 1, page 466, list the uses for each type of
electromagnetic wave.
2. Look at page 470 and write a description of how an incandescent
light bulb works.
3. Page 469 # 4, 6, 9, 11
4. Page 476 # 2,3,6,7,8,9
Lesson 1 - Light and Light Production
Physics: Optics Unit
Page 3 of 3
Name: _________________________________________
Date: ______________________
THE RAY MODEL OF LIGHT
Read pages 479 – 481
_______________

Light travels in a

A light ray is a line on a diagram that
line.
___________ the direction and path that light
is travelling.

A luminous object radiates light in
___ directions.
This would be indicated in a ray
diagram with lines and arrows in many directions.
_____________ object.

All or almost all light will pass through a

Some light passes through and some light is absorbed or reflected in a
________________ object.

All light is absorbed or reflected in an
___________ object.
________________________ –
the use of light rays to determine how light
behaves when it strikes an object.
____________________ –
the light emitted from a source that strikes an object.
_________________________ –
the light that bounces off an object.
Flat Mirrors
Mirrors reproduce images by
_________________ light.
A flat mirror is known as a plane mirror, and consists of a piece of glass coated on one side with a
thin layer of shiny material such as silver or aluminum.
The path light takes when light hits a plane mirror is
____________.
_____________
____________.
will be equal to the angle of
Lesson 2: The Ray Model of Light
Physics: Optics Unit
The angle of
Page 1 of 2
Name: _________________________________________
Date: ______________________
Some terms:
________________ –
the incoming ray that strikes the surface
________________ –
the ray that bounces off a reflective surface
________________–
the perpendicular line to a mirror surface
_________________ –
at a right angle (90°) to the surface
_____________________ –
the angle between the incident ray and the normal
_____________________ –
the angle between the reflected ray and the normal
Homework: Page 481, Questions 2, 3, 5
Lesson 2: The Ray Model of Light
Physics: Optics Unit
Page 2 of 2
Name: _________________________________________
Date: ______________________
THE LAWS OF REFLECTION
Read pages 484 - 486
Two Laws of Reflection:
1. ________________________________________________
_________________________________________________
2. _________________________________________________
_________________________________________________
Reflecting Light Off Surfaces
If a set of parallel light rays all hit a flat surface, the angle of incidence for all rays
_____________,
____________
so all the reflected rays will be parallel to one another.
Reflection: the reflection on light off a
__________
surface such as
a mirror or polished metal.
If a set of parallel light rays all hit an
______________, the angle of incidence for each
ray would be different, so the reflected rays will be scattered and not parallel to one another.
_________
Reflection: the reflection of light off an
_______or dull surface such as
crumpled foil or a sheet of paper.
IMAGES IN PLANE MIRRORS
Read pages 488 – 492
When we see an image in a plane mirror, the object appears to be located
____________
mirror. Our brain thinks the light source is coming from behind the mirror. The image is known as
a
______________________.
Lesson 4: Laws of Reflection/Images in Plane Mirrors
Physics: Optics Unit
Page 1 of 3
Name: _________________________________________
Virtual image – an image formed by light coming from an
the image is formed by rays that
Date: ______________________
_____________________;
________ from the location of the image.
Light rays and the laws of reflection are used to determine where and how images are formed in a
plane mirror.
Source
Apparent Source
Actual
Object
Virtual Image
The above diagram shows how the eye
from the object
________
___________ of an object in a mirror.
the mirror, and the angle of incidence
reflection. The brain thinks the object is
The light rays
________ the angle of
_________________________.
In a plane mirror:
1. ______________________________________________
_______________________________________________
2. _________________________________________________
To draw a virtual image of an object in a plane mirror, a number of
lines must be drawn. By
_____________
________the end-points of the mirror side of the lines, the
_______of the virtual image can be determined.
object-image line
object-image line
Lesson 4: Laws of Reflection/Images in Plane Mirrors
Physics: Optics Unit
Page 2 of 3
Name: _________________________________________
Date: ______________________
Image Description
There are 4 properties of an image:
______ of image compared to the object
- smaller, same, or larger.
________________ of the image which is the orientation compared to the object, either
upright or inverted.
__________ of the image.
__________of image, either real or virtual (real images occur when light rays arrive at the
image location)
The acronym SALT can be used to remember these 4 properties.
Plane mirror images are always the
_________________________
___________________________________________________
When you look a printed image in a plane mirror, the letters appear to
_______________.
That is why emergency vehicles have their names written backwards on their front hoods – so
drivers can read the printing in their rear-view mirrors.
Homework: Page 486, Questions 2, 4, 5
Page 493, Questions 1, 3, 4, 5a
Draw an object and its image in a plane mirror in the blank space below.
Be sure to use a ruler so you can accurately locate the virtual image.
Now, add an eye to the diagram, and using light rays, indicate how the
image reaches the eye. Be sure to use a protractor. See Figure 7 and
8 on page 491 if you have any trouble.
Lesson 4: Laws of Reflection/Images in Plane Mirrors
Physics: Optics Unit
Page 3 of 3
Name: _________________________________________
Date: ______________________
IMAGES IN CURVED MIRRORS
Read pages 496 - 500
There are two types of curved mirrors, both shaped like a section of a spherical surface:
________________ – reflection is from the inner surface of the spherical section.
________________ –
reflection is from the outer surface of the spherical section.
CONCAVE MIRRORS
Terms:
________________________ –
the centre
point of the sphere that would be formed with the mirror
section
______________________ –
the line that
goes through the centre of the mirror and the centre of
curvature
__________ –
the point on the mirror where the
principal axis crosses the centre of the mirror
__________ –
the point at which light rays that are
parallel to the principal axis converge when they are
reflected off a concave mirror
____________ – to meet at a common point
_________ – an image that can be seen on a screen as
a result of light rays arriving at the screen location.
Concave mirrors are used in flashlights, car headlights and searchlights, to reflect the source light
rays. In reflecting telescopes, they are used to focus an image from incoming parallel rays.
Lesson 6: Images in Curved Mirrors
Physics: Optics Unit
Page 1 of 4
Name: _________________________________________
Date: ______________________
To locate an image in a converging (concave) mirror:
1.
Draw a light ray from the top of the object parallel to the principal axis. This ray will
reflect through the focus point.
2. Draw a light ray from the top of the object through the focus point. This ray will reflect
parallel to the principal axis.
3.
Draw the top of the object image where the two reflected rays intersect (cross). Extend
the object line to the principal axis. This is where the bottom of the object image is.
Some examples:
Characteristics of the Image
a) Object beyond
C
Real
Inverted
Smaller
Between C and F
b) Object at C
Real
Inverted
Same size as
object
At C
c) Object at F
No image
Reflected rays
are parallel
d) Object between F and C
Real
Inverted
Larger
Beyond C
C
Lesson 6: Images in Curved Mirrors
Physics: Optics Unit
F
Page 2 of 4
Name: _________________________________________
Date: ______________________
CONVEX MIRRORS
Terms:
Centre of curvature – the
centre point of the sphere
that would be formed with the mirror
section, located ______________
the mirror
Diverge – to spread apart
Focus – the point at which light rays that are parallel to the principal axis appear to originate from,
located behind the mirror
In a convex mirror, the image appears to come from behind the mirror. The rays reflected off a
convex mirror always diverge, so the reflected rays will never cross to form a real image. The
_________
formed will always be smaller and upright. They are used as security mirrors and
side-view mirrors in vehicles, because it allows a wider field of view.
To locate an image in a diverging (convex) mirror:
1.
Draw a light ray from the top of the object parallel to the principal axis. The ray will
appear to come from the focal point of the mirror. The reflected ray should be drawn from
the focal point, through the point of incidence of the incident ray, then continued in a
straight line out of the mirror.
2. Draw a light ray from the top of the object that intersects the principal axis at the focal
point of the mirror. The reflected ray will be parallel to the principal axis, drawn from the
point where the incident ray hit the mirror.
3. The top of the virtual image will be located where the two rays behind the mirror intersect.
The bottom of the object will be drawn on the principal axis.
Lesson 6: Images in Curved Mirrors
Physics: Optics Unit
Page 3 of 4
Name: _________________________________________
Example:
Date: ______________________
Characteristics of the Image
Virtual
Upright
Smaller
Between F and the mirror
Homework: 1. Draw an example of the image of an object located between F and the vertex of a
concave mirror. Use Figure 10 on page 499 for help if necessary.
2. Page 500, Questions 2, 3, 4, 6 (refer to your drawing from 1.), 8, 9, 10
3. Fill in the following table:
CONVERGING (CONCAVE) MIRROR
Object
Location
Beyond C
Image Size
Image
Attitude
Image
Location
Image Type
At C
Between C and
F
At F
Between F and
the vertex
Lesson 6: Images in Curved Mirrors
Physics: Optics Unit
Page 4 of 4
Name: _________________________________________
Date: ______________________
CONCAVE MIRROR MAGNIFICATION EQUATIONS
Concave mirrors magnify images, either making them
Magnification can be considered a
_________
_______________.
of the
_______________
____________________________________________________
Magnification =
____________
or
𝑀=
ℎ𝑖
ℎ0
where M = magnification
hi = image height
ho = object height
Magnification can
_____ be calculated by taking the ratio of the ___________
________________________________________________
Magnification =
______________
𝑀=
𝑑𝑖
𝑑0
where M = magnification
di = image distance to mirror
do = object distance to mirror
Remember all measurements must be in the
Lesson 7: Concave Mirror Equations
Physics: Optics Unit
________________________!
Page 1 of 2
Name: _________________________________________
Date: ______________________
Example:
A candle is placed 22 cm from a concave mirror. A virtual image is produced 53 cm from the mirror.
What is the magnification?
(USE THE GRASS METHOD)
Given:
object distance do = _______ cm
image distance di = _________ cm
Required: magnification M = ?
Analysis:
𝑀=
𝑑𝑖
𝑑0
Solution:
𝑀=
𝑑𝑖
𝑑0
=
=
Statement: The magnification is _______________
Homework:
1.
A concave mirror produces an image on a wall that is 24.0 cm high from an
object that is 6.0 cm high. What is the magnification of the mirror?
2. A candle is placed 75 cm away from a concave mirror. A real image is seen 50
cm away from the mirror. What is the magnification?
3. A slide projector has a magnification of 50. How wide will the image be is
the slide is 2.8 cm wide?
4. A concave mirror has a magnification of 12. If a real image of an insect is
seen 6.0 cm from the mirror, how far away is the insect from the mirror?
Lesson 7: Concave Mirror Equations
Physics: Optics Unit
Page 2 of 2
Name: _________________________________________
Date: ______________________
REFRACTION
Read pages 515 - 519

When light travels
water to air,

_______________________________,
___________.
such as from
This bending is known as refraction.
As light travels from one medium to another, some light may be
_______________
__________________________________.
_________________________________.
This is known as
Mirrored sunglasses are an
example of this.

As light enters a medium
__________, it slows down, so the _____________
______________ than 3.0 x 108 m/s.
Two rules apply:
1.
The incident ray, the refracted ray and the normal are
_____________.
___________________
The incident ray is in the first medium and the refracted ray is
in the second medium. The normal is
___________________________
______________________________________________.
2.
Bending: If the speed of light is
first, the light ray
__________ in the second medium than in the
_________________________.
If the speed of light is
_____________ in the second medium, the light ray will ______________
________________________.
Homework: Page 519, Questions 2, 3, 4
Lesson 8: Refraction
Physics: Optics Unit
Page 1 of 1
Name: _________________________________________
Date: ______________________
THE INDEX OF REFRACTION
Read pages 524-525
________________
in a medium: the
________ of the speed of light in a
___________ to the speed of light in __________________.
___________
n – index of refraction in a medium, n is a dimensionless
quantity
c–
______ of light in a _________ 3.00 x 108 m/s
v–
_______ of light in the _____________
Snell’s Law
Snell, a Dutch scientist noted that:
______________
θi - ___________ θr – _____________
n – index of refraction
Rearranging this, we get:
𝑛=
sin 𝜃𝑖
sin 𝜃𝑟
This is another way to calculate the index of refraction,
________
needing to
____________________________.

The index of refraction is 1.00 in a vacuum, 1.0003 in air, and
________________________________________.

The
_____________
the refractive index in a medium, the
____________________________________.
Lesson 9: Index of Refraction and Total Internal Reflection
Physics: Optics Unit
Page 1 of 4
Name: _________________________________________
Date: ______________________
Example 1
If the speed of light in fluorite is 2.10 x 108 m/s, what is the index of refraction in fluorite?
Given:
__________________ : v = 2.10 x 108 m/s
__________________ : c= 3.00 x 108 m/s
Required: _____________________________: n = ?
Analysis: ______________
Solution: n =
=
Statement:
______________________________________.
Example 2
If the index of refraction of diamond is 2.42, what is the speed of light in diamond?
G :
n = 2.42
c = 3.00 x 108 m/s
R : speed of light in diamond v =?
A :
S :
S: __________________________________________________________________
Homework: Page 525, Questions 1, 2, 3, 4, 7
Lesson 9: Index of Refraction and Total Internal Reflection
Physics: Optics Unit
Page 2 of 4
Name: _________________________________________
Date: ______________________
TOTAL INTERNAL REFLECTION
Read pages 526 - 531

When light travels
_____________________,
some light is
_____________________________________.

When light speeds up as it passes from one medium to another (such as when light passes
from glass into air), it
___________ from the normal at the ___________ of
the two medium. The
______ of ___________
will
______________
_________________________________.

As the angle of
________________,
_______.
When the angle of incidence is
the angle of
___________
______ that the angle of
_________________ the angle of incidence is at the ______________.

When the
will be
_________ ray is ________ than the critical angle, __ of the light
____________
into the first medium. This is known as
________________________________.
_______________ – the angle of incidence that results in an angle of refraction of 90˚.
______________________ – light reflects completely off the inside wall of a denser
medium, instead of passing into a less dense medium. This occurs when the angle of incidence is
larger than the critical angle.
In the figure, as the angle of
incidence increases, so does
the angle of refraction.
Eventually, the angle of
refraction exceeds 90˚, and
total internal reflection
occurs.
Lesson 9: Index of Refraction and Total Internal Reflection
Physics: Optics Unit
Page 3 of 4
Name: _________________________________________
Two
_____________________
1)
Light is travelling more
for total internal reflection:
______________________ than in the second.
2) The angle of incidence is large enough so that
second medium. The
Date: ______________________
_________
will be
______________ occurs in the
________ reflected back into the first
medium.
APPLICATIONS OF TOTAL INTERNAL REFLECTION
Diamonds: Diamonds have a
_________ of refraction and as a result the critical angle is
small (24.4˚). A large amount of light will be reflected internally, before exiting the stone. The
sparkle is enhanced by the method of cutting the stone.
Fibre Optics: Fibre optic cables are made of glass or plastic with a
The light stays
__________, instead of refracting out.
________________ and signalling.
________ critical angle.
Light can be used for
Fibre optic sensors are commonly used in automated
manufacturing to sense parts remotely.
Triangular Prisms: Triangular prisms are used in devices such as periscopes and
instead of mirrors to redirect light. Proper
___________ of the prisms allows light to be
_______ back into the prism, and then out on another side.
can change the direction of light by
_________
_________
Depending on orientation, a prism
_______ (one total internal reflection) or
(two total internal reflections).
Copy figure 8, page 529 from the text in the blank space below:
a) One internal reflection
b) Two internal reflections
Homework: Page 531, Questions 1, 2, 3, 4, 8, 9
12.2 pages 520-521: Read over and be ready to do
this lab.
Lesson 9: Index of Refraction and Total Internal Reflection
Physics: Optics Unit
Page 4 of 4
Name: _________________________________________
Date: ______________________
PHENOMENA RELATED TO REFRACTION
Read pages 535 - 539
In nature,
______________________
_______________:
really are. This is due to the
Objects in water
many different phenomena.
_______ to be in shallower water than they
_______ of light between the air and water.
What happens: If you stand at the side of a swimming pool, objects under the water appear to be
_________ the surface than they really are. If you look through glass or clear plastic, a
similar effect can be seen.
For example, a fish seems to be nearer the surface than it really is:
This is caused by refraction of light at the
_______
of the water. The magnitude of the
effect is related to the refractive index of the media involved. The
_____ depth of the fish is
___ and its _______ depth is ___. Light from the fish reaches the eye. The brain
perceives the light as coming in a ______ line from the fish, creating a ________ image
at the apparent depth A. The fish appears __________ than it actually is.
Mirage – Water on Pavement: The
of
______
image of a puddle of water on pavement is the result
_______________________________
layers of air of different
temperatures.
What happens: An image of light from the sky is produced as light refracts through air of
different densities. The air
______ ground is ____, so it the refractive index gets lower as
Lesson 11: Phenomena Related to Refraction
Physics: Optics Unit
Page 1 of 2
Name: _________________________________________
the light passes through closer to the hot ground. At the
internal reflection occurs, then as this light is
is
Date: ______________________
_________
air layer,
_____
_____________ through cooler air layers, it
________ to the observer, causing an image of the sky.
Shimmering: Images appear to shimmer due to light
This image is perceived as water.
_____________
________________ through air layers of _________ temperatures.
What happens: Surface air is warmer than air at higher levels, so light travels faster in surface
layers. As a light ray passes from colder layers to warmer layers, the ray will bend farther and
farther away from the normal, and eventually total internal reflection occurs. This results in
multiple images being perceived.
Rainbow: The refraction of sunlight and
______________________
water droplets
causes rainbows.
What happens: As light enters a raindrop, the light
spectrum travels
___________
_________.
Each colour in the visible
different speeds, which results in
____________
(the separation of white light into its separate colours). Violet light travels the slowest and red
the fastest. When the light
reflection occurs. The
_____ the other side of the raindrop, refraction and partial
_______ light will then ______
when it exits the raindrop.
Refracted light is what the eye sees as a rainbow – visible white light dispersed into its constituent
colours. The sun must be behind the eye for this to occur.
Homework: Page 539, Questions 2,4,6,7
Review for Chapter 12 Quiz: pg. 542 – 543,
Questions 1 – 9, 10, 12, 13, 14, 15, 16, 18, 20,
21,22
Lesson 11: Phenomena Related to Refraction
Physics: Optics Unit
Page 2 of 2
Name: _________________________________________
Date: ______________________
LENSES AND THE FORMATION OF IMAGES
Read pages 551 - 553
Everyone sees the world through the lenses on their eyes, which _______ light
(and therefore images) onto the retina. Lenses are used in eyeglasses and contacts to
________ the vision in those whose own natural lenses don’t work properly.
used to
Lenses are also
_____________________________________
CONVERGING LENSES
A converging lens
the
_____________
________ of the lens.
rays so that they all pass through a
________ on
A converging lens is thickest in the middle and thinnest at the
edge.
F’ – secondary focus
Because light rays could go through the lens from either direction, we label the focus points on
either side of the lens. The
of the lens as the
_____________ the converging lens is on the ________
______ rays.
DIVERGING LENSES
A diverging lens
________________ rays so that they ______
on the
_______
of the lens. A diverging lens is thinnest in the middle and thickest at the edge.
Lesson 12: Lenses and the Formation of Images
Physics: Optics Unit
Page 1 of 2
Name: _________________________________________
If the diverging rays are projected backwards, it
principal focus. The
lens as the
________
Date: ______________________
as if they come from F, the
__________ of a diverging lens is on the ___________
of the
______________.
Homework: Page 553, Questions 2,3,5,6
Read Section 13.2 pages 554 – 555 and
prepare data chart for lab.
Lesson 12: Lenses and the Formation of Images
Physics: Optics Unit
Page 2 of 2
Name: _________________________________________
Date: ______________________
IMAGES IN LENSES
Read pages 556 - 560
Two things affect the characteristics of images formed by a lens:
 __________________________________________
 __________________________________________
To find the image characteristics, you need to draw the incident and refracted light rays from the
original object.
___________________________________________
____________________________________________________
Emergent ray: the light ray that leaves a lens after refraction.
If we look at a thick rectangular prism, the incident ray gets refracted
__________ –
first
when the ray enters the prism from the air (the air-glass boundary), and then second when the
refracted ray in the prism exits into air (the glass-air boundary). We can see in figure 1 that the
emergent ray is
_________ to the incident ray.
There is a
________
sideways
displacement between the incident and emergent rays. If the prism is made much
can see that the displacement between the two rays is much
Lesson 14: Images in Lenses
Physics: Optics Unit
______,
we
_____________.
Page 1 of 4
Name: _________________________________________
Date: ______________________
Locating the Image in a Converging Lens
To locate the image in a converging lens, follow at least two of these steps:
1.
Draw a light ray
_______________________________________
________________________________________________.
From this point,
________________________________________
________________________________________________.
2.
Draw a light ray
________________________________________
_________________________________________________
From this point,
________________________________________
_________________________________________________
3.
Draw a ray
___________________________________________
_________________________________________________
(Note: at this point of the lens, the lens acts like a very thin rectangular prism, so there is
no noticeable sideways displacement of the ray).
After the refracted light rays are drawn,
This will be the top of the image. The
_______________.
Lesson 14: Images in Lenses
Physics: Optics Unit
_____________
_______
where the lines all intersect.
of the image will be located on the
Draw the object.
Page 2 of 4
Name: _________________________________________
As you move the object
____________,
the image gets
Date: ______________________
_______.
For an object
placed between F’ and 2F’, at 2F’ and beyond 2F’, the image is always inverted and real.
If the object is place between F’ and the lens, the rays diverge, but the brain
________
_______________, so it seems as if the image is behind the object – a virtual image.
Locating the Image in a Diverging Lens
To locate the image in a diverging lens, follow at least two of steps 1, 2 and 3. Then do step 4:
1.
Draw a ray
______________________________________
_______________________________________________
Draw a ray
_______________________________________
________________________________________________
___________________The extended line is the refracted ray.
2. Draw a ray
_______________________________________
________________________________________________
________________________________________________
________________________________________________.
Extend the line on both sides of the lens.
3.
Draw a ray
________________________________________
_________________________________________________
________________________________________________.
4.
The
_____________________________________________
______________________________.
Lesson 14: Images in Lenses
Physics: Optics Unit
The
_____________
Page 3 of 4
Name: _________________________________________
Date: ______________________
___________________________________.
In a diverging lens, the
__________________________________________
________________________________________________.
Our brains extend the diverging rays back to create this virtual image.
Homework: Complete “Images in Lenses “Worksheet
Page 561, Questions 1, 2, 3, 4, 6
Lesson 14: Images in Lenses
Physics: Optics Unit
Page 4 of 4
Name: _________________________________________
Date: ______________________
THE LENS EQUATIONS
Read pages 562 - 566
We have studied a method using ray diagrams to determine image characteristics of images formed
by lenses. It is also possible to
___________________________________
__________________________________________
Converging Lens Terminology:
do =
_______ from the _______ to the optical centre
di = ___________ from the __________ to the optical centre
ho= ___________ of the ______________
hi = ___________ of the __________
f = _______________________ of the lens; the ____________from the
optical center to the principal focus (F)
The Thin Lens Equation
This equation relates focal length to object and image distances.
1
1 1
+ =
𝑑𝑜 𝑑𝑖 𝑓
Rules:

Object distances (do) are always _________

Image distances (di) are _________ for ______ images (opposite side of lens from object)
and __________for ___________ images (same side of lens as object).

The focal length (f) is _________________________________________________
__________________________________________________________________
Lesson 15: The Lens Equations
Physics: Optics Unit
Page 1 of 3
Name: _________________________________________
Date: ______________________
Example:
A magnifying glass has a converging lens that is held 2.00 cm above a page. If the image produced
by the lens is 3.60 cm away and virtual, what is the focal length of the magnifying glass?
Given: distance from the object to optical center d o =
________
distance from the virtual image to the optical center d i =
_______
Required: focal length of the lens f
Analysis: Thin lens equation
Solution:
1
𝑓
1
𝑑𝑜
+
1
𝑑𝑖
=
1
𝑓
=
Statement: The focal length of the lens is ___________________
Diverging Lens Terminology
do = distance from the object to the optical centre
di = distance from the image to the optical centre
ho= height of the object
hi = height of the image
f = focal length of the lens; the distance from the optical center to the
principal focus (F)
Example: A diverging lens has a focal length of 14 cm. A virtual image of a candle is located 7.0 cm
in front of the lens. Where is the actual candle located?
Given: f = -14 cm
di = -7.0 cm
Required: do = ?
Lesson 15: The Lens Equations
Physics: Optics Unit
Page 2 of 3
Name: _________________________________________
Analysis:
1
𝑑𝑜
+
1
𝑑𝑖
=
Date: ______________________
1
𝑓
Solution:
Statement: The object is _____________ from the lens.
The Magnification Equation
Like mirrors, we can use a
_____________________ for lenses.
𝑀=
ℎ𝑖
𝑑𝑖
=−
ℎ𝑜
𝑑𝑜
The sign rules above apply, and as well:

Object height (ho) and image height (hi) are
_________
________ from the principal axis and _________
when they are measured
when they are measured
__________.

Magnification (M) is
for an
_________ for an ________ image and __________
____________ image.
Example:
A pinecone of height 5.0 cm is placed in front of a converging mirror. A real, inverted image of
height 15.0 cm is visible on the opposite side of the lens. What is the magnification of this lens?
Given: ho = 5.0 cm
hi = -15.0 cm
Required: M = ?
Analysis: 𝑀 =
ℎ𝑖
ℎ𝑜
Solution: 𝑀 =
Statement: The lens magnification is _______________
Homework: Page 566, Questions 1, 2, 4, 6, 8
Copy Table 1, page 566 Sign Conventions for Lenses into notes.
Lesson 15: The Lens Equations
Physics: Optics Unit
Page 3 of 3