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Chapter 11 Review
Mirrors & Lenses
Category: Reflection
What is an angle of incidence?
The angle between
an incident ray and
the normal of an
optical device.
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Category: Lenses
What is the difference in shape
between a convex and a concave lens?
A convex lens is thicker
whereas a concave lens
is thinner in the middle
than at the outside
edges.
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Category: Images
What is an optical device? Give
three examples.
An optical device is a device that
produces an image of an object.
Examples: camera, LCD
projector, overhead projector,
magnifying glass, glasses, eyes,
telescopes, microscopes, movie
projectors, etc.
Category: Mirrors
What is the principal axis of a curved
mirror?
A line through the
centre of the mirror
that includes the focal
point (principal focus).
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Category: Mirrors
Describe the size, attitude, location,
and type of image you get in a plane
mirror
The image is the same
size as the object,
upright, behind the
mirror, and is virtual.
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Category: Images
What is a virtual image?
An image that cannot be
placed on a screen and
can only be seen by
looking at or through an
optical device (light rays
diverge from the optical
device).
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Category: Mirrors
Why does an image appear behind
a plane mirror?
Rays reflecting off a plane
mirror diverge. It you
extend these reflected
rays back, they would
converge behind the
mirror.
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Category: Reflection
If an incident ray is at an angle of 20
degrees from the surface of a mirror (not
from the normal), what will be the angle of
reflection?
If the incident ray is at an angle of 20
degrees from the mirror, then the angle of
incidence is 90 – 20 = 70 degrees, so the
angle of reflection is also 70 degrees.
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Category: Lenses
In what situation would a light ray passing
through a lens not refract at all?
When a light ray hits a lens at 90 degrees
(along it’s normal or principal axis), it will
not refract.
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Category: Mirrors
Describe the size, attitude, location, and
type of image obtained by holding an object
very far beyond the focal point of a concave
mirror.
The image is smaller than the object,
inverted, in front of the mirror, and real.
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Category: Mirrors
What type of mirror is a cosmetic
mirror and why does a person have to
be close to it for it to be useful?
Concave. The person must
be within the focal point
in order to get a larger
(magnified) image.
Category: Lenses
How is a convex lens similar to a concave
mirror?
They both cause light rays to converge
at a focal point. They also form similar
images in terms of size, attitude, and
type depending on how far away the
object is from the lens or mirror.
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Category: Reflection
Give two examples of ways to diffuse light
in a room so that it is easier on the eyes.
Using frosted light bulbs, irregular surfaces on
ceilings (such as stucco), using lampshades,
avoiding too many mirrors or direct light
sources.
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Category: Mirrors
Describe the size, attitude, location, and
type of image obtained by holding an object
just beyond the focal point of a concave
mirror.
The image is larger than the object,
inverted, in front of the mirror, and real.
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Category: Reflection
What is diffuse reflection?
The reflection of light off an irregular
surface so that it scatters in many
directions and an image is not formed.
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Category: Refraction
Does a light ray speed up or slow down
as it passes from air to water? Does it
bend away from or towards the
normal?
The light ray slows down and bends towards
the normal.
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Category: Mirrors
Why does the passenger side-view mirror of
a car read “Objects in mirror are closer
than they appear”?
A side-view mirror is a
convex mirror, used because
it gives a wide side view. The
image in a convex mirror is
always smaller, giving the
illusion that an object is
farther away than it really is.
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Category: Mirrors
How would you describe the reflected
rays from a convex mirror?
Diverging (they spread apart).
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Category: Images
What is a real image?
An image that can be placed on a screen at
that can be seen without looking at or
through an optical device (light rays
converge from the optical device).
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Category: Mirrors
How would you describe the reflected
rays from a concave mirror?
Converging (they come together).
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Category: Reflection
What is specular reflection?
The reflection of
light off a smooth,
shiny (regular)
surface so that an
image is formed.
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Category: Refraction
What is refraction?
The bending of light as it passes from one
material to another (due to a change in
speed).
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Category: Mirrors
What type of mirror is used in a flashlight
and why?
A concave mirror is used because it
reflects the light rays from the bulb into
a concentrated, parallel beam.
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Category: Mirrors
In what situation would a concave
mirror produce an upright, virtual
image?
When the object is within the focal point of
the mirror (i.e. it is very close to the
mirror).
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Category: Lenses
What is a lens?
A curved, transparent device that causes
light to refract as it passes through. It
produces an image of an object.
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Category: Reflection
What is the difference between an incident
ray and a reflected ray?
An incident ray is a ray
of light that travels
towards a reflecting
surface, whereas a
reflected ray bounces
off a reflecting surface.
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Category: Mirrors
What type of mirror is a
surveillance mirror? Why?
It is a convex mirror
because it reflects light
rays from all parts of a
room towards a person’s
eyes, thus giving a wide
view.
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Category: Mirrors
Describe the size, attitude, location, and
type of image obtained by holding an object
in front of a convex mirror.
The image is smaller, upright, behind the
mirror, and virtual.
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Category: Lenses
How would you describe light rays
passing through a convex lens?
They converge (come together).
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Category: Refraction
Describe why the straw appears bent in the
glass of water.
The light rays coming from the
part of the straw that is under
water change speed and
direction as they pass from
water to air towards your eyes.
This makes them appear to
come from a place under the
water where the straw actually
isn’t, so the straw appears bent.
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Category: Mirrors
What is the difference in shape
between a concave and a convex
mirror?
A concave mirror is one that
curves inwards (the
reflecting surface is on the
inside curve). A convex
mirror curves outwards (the
reflecting surface is on the
outside curve).
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Category: Lenses
Describe the size, attitude, and type
of image produced by a concave lens.
The image is smaller, upright, and
virtual.
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Category: Reflection
Give two examples of specular
reflection.
Light reflecting off a mirror, shiny metal,
the surface of still water, etc.
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Category: Lenses
What type of lens does a magnifying glass
use? Why must you hold the object you are
observing close to the lens?
Convex lens. You must have
the object within the focal
point in order for its image
to be enlarged (magnified).
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Category: Lenses
Name three devices that use lenses.
Camera, LCD projector, glasses,
contacts, magnifying glass,
microscope, eyes, etc.
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Category: Mirrors
Describe the size, attitude, location, and
type of image obtained by holding an object
within the focal point of a concave mirror.
The image is larger, upright, behind the
mirror, and virtual.
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Category: Mirrors
What is the focal length of a
curved mirror?
The horizontal distance
between the focal point
and the middle of the
mirror.
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Category: Lenses
What happens to parallel light rays
that strike a concave lens?
They diverge (spread apart).
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Category: Mirrors
What is the focal point of a
concave mirror?
The point at which all
incident parallel light rays
are reflected through
(where they converge
after being reflected).
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Category: Reflection
What are the two laws of reflection?
1. The angle of incidence
equals the angle of
reflection.
2. The incident ray, normal,
and reflected ray all lie in
the same plane.
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