Bai 2 huong dan thtn ve hien tuong phan xa anh sang

THE LAW OF REFLECTION
(P 32 01)

Apparatus
GSN 246
POG 465
POG 461
POG
400.03
POG 110
KAL
60/5A

Adhesive magnetic board
Ray box, 6V 20 W
Diaphragm 1 and 2 slits
Optical disc

1
1
1
1

Plane mirror
Connecting lead
Power supply

1
2
1

Procedure:


Put the plane mirror on the optical disk as shown.
The ray of light hits the mirror at point F. Point F is the center of the optical
disk. The ray of light is reflected back on it self. The direction of this ray is
termed the perpendicular.



Move the ray box until The ray hits the mirror at an angle ° .
The angle of incidence (the angle between the normal line (N) and the
incoming ray). The angle of reflection (the angle between the normal line (N)
and the reflected ray r) is seen to be 30° as well.

Optics Panel Type |

1


After experimenting with different angles of incidence and reading off the
corresponding angles of reflection it may be found that:
the angle of incidence is always of the same magnitude as the angle of
reflection .

2

| Optics Panel Type

ROTATING MIRROR
(P 32 02)

Apparatus:
GSN 246
POG 465
POG 461
POG
400.03
POG 110
KAL
60/5A

Adhesive magnetic board
Ray box, 6V 20 W
Diaphragm 1 and 2 slits
Optical disc

1
1
1
1

Plane mirror
Connecting lead
Power supply

1
2
1

Ruler
Whiteboard marker

1
1

Procedure:




Put the plane mirror on the optical disk as shown in the figure.
Draw N Perpendicular to the mirror with the whiteboard marker.
Position the the ray box so that the incoming ray hits point F and the angle of
incidence is = 30°.



Rotate the mirror 10° and draw perpendicular N .

Optics Panel Type |

3


It can be observed that the reflected ray rotates 20°. In rotating the mirror by
an angle an angle of incidence + ) and thus an angle of reflection + )
is produced.
The total deviation of the reflected ray is 2.

4

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REGULAR REFLECTION
(P 32 03)

Apparatus:
GSN 246
POG 465
POG 462
POG 110
KAL 60/5A
POF 220.01
POF 220.02

Adhesive magnetic board
Ray box, 6V 20 W
Diaphragm 3 and 5 slits
Plane mirror
Connecting lead
Power supply
Color filter, red
Color filter, blue

1
1
1

1
2
1
1
1

Procedure:





Insert a diaphragm three slits into the ray box.
Setup the ray box and the mirror as shown in figure.
Place the color filter on outer light rays.
These three light rays represent a parallel beam of light.
Turn a parallel light rays as “V-shaped” to ilustrate the principle of regular
reflection.

The parallel rays remain parallel to one another even after reflection, yet their
order is reversed; after being reflected, the blue light ray can be found on the
outside of the beam of light.

Optics Panel Type |

5


DIFFUSE REFLECTION
(P 32 04)

Apparatus:
GSN 246
POG 465
POG 462
POG 110
KAL 60/5A

Adhesive magnetic board
Ray box, 6V 20 W
Diaphragm 3 and 5 slits
Plane mirror
Connecting lead
Power supply
Scissors
Aluminum foil

1
1
1
1
2
1

Procedure:



The aluminum foil is first crumpled up, then wrapped around the plane mirror.
Place the mirror onto the adhesive magnetic board.

The parallel beam of light is reflected in every possible direction (diffracted,
diffuse reflection).

The uneven surface of the aluminum foil can be thought of as a large number of
small mirrors, inclined toward each other at varying angles.

6

| Optics Panel Type


IMAGE POINT ON A PLANE MIRROR
(P 32 05)

Apparatus:
GSN 246
POG 465
POG 461
POG 110
POG 480.02
KAL 60/5A

Adhesive magnetic
board
Ray box, 6V 20 W
Diaphragm 1 and 2 slits
Plane mirror
Arrow, L=80 mm
Connecting lead
Power supply

Whiteboard marker
Ruler

1
2
2
1
1
4
1
1
1

Procedure:



Draw a straight line a using the whiteboard marker.
Place The two ray box are so that the two rays intersect at object point M and
then reflected in the plane mirror.

The light rays proceeding from M are drawn in prior to and following reflection.
Since the reflected light rays do not intersect afterward, no real image point,
instead merely a light spot, exists.


The observer's eye is now drawn in.
It looks along the reflected light rays toward the mirror. The human eye does
not perceive the "bend" along the path of the light rays but rather extends
them further according to a straight line. The extensions of the reflected light

rays intersect at the imaginary point M'.
M and M' lie symmetrical to each other about the same axis, the plane mirror.

Optics Panel Type |

7


VIRTUAL IMAGE ON A SMOOTH MIRROR
(P 32 06)

Apparatus:
GSN 246
POG 465
POG 461
POG 110
POG 480.02
KAL 60/5A

Adhesive magnetic board
Ray box, 6V 20 W
Diaphragm 1 and 2 slits
Plane mirror
Arrow, L=80 mm
Connecting lead
Power supply
Whiteboard marker
Ruler

1

2
2
1
1
4
1
1
1

Procedure:

8



Set up the experiment according to the figure.
Two parallel light rays proceed from the tip S and the foot F of the object G
(arrow, l = 80 mm) which are then reflected back on themselves. These light
rays and the extensions of the reflected rays are drawn in.



Turn the lower ray box so that the two light rays intersect at the tip S of the
object.
The light ray proceeding from S, the reflected ray and its extension are drawn
in. The result is the virtual image point S'.

| Optics Panel Type



Turn the upper ray box so that the two light rays intersect at the foot F of the
object G.
The light ray proceeding from F, the reflected ray and its extension are drawn
in. The result is the virtual image point F'. The virtual image B is an arrow from
F' to S'.

Optics Panel Type |

9


CONCAVE MIRROR

(P 32 07)

Apparatus:
GSN 246
POG 465
POG 461
POG 462
POG 101
KAL 60/5A

Adhesive magnetic
board
Ray box, 6V 20 W
Diaphragm 1 and 2 slits
Diaphragm 3 and 5 slits

Mirror, flexible
Connecting lead
Power supply
Whiteboard marker
Ruler

1
1
1
1
1
2
1
1
1

Procedure:


Insert a diaphragm with one slit the ray box.
The point S is marked at a distance of 35 cm: this serves as the vertex of the
concave mirror. The ends of the flexible mirror span points that lie at a distance
of 6 cm perpendicular to the vertex, situated symmetrically to the optical axis
(a=b).



Remove the diaphragm.
A narrow beam of light parallel to the axis is created. The rays of light reflected
in the concave mirror result in a catacaustic curve, the apex of which is the

focus F.

10 | Optics Panel Type


Measurement example:
Distance SF = f = 2.5 cm


Reverse the raybox, a divergent beam of light is generated which is then
reflected from the concave mirror.



Insert the diaphragm with five slits.
Each of the focal points (i.e. the points where the reflected rays intersect the
optical axis) is marked.

Concave mirrors consisting of sections of a circle (or, spatially speaking,
sections of a sphere) do not have a single focal point but rather a focal spot.
Ideally, the following holds true: distance SF = f = r 2 .

Optics Panel Type | 11


PATH OF RAYS IN A CONCAVE MIRROR
(P 32 08)

Apparatus:
GSN 246

POG 465
POG 461
POG 101
KAL 60/5A




Adhesive magnetic board
Ray box, 6V 20 W
Diaphragm 1 and 2 slits
Mirror, flexible
Connecting lead
Power supply
Whiteboard marker

1
2
2
1
4
1
1

The light ray moving along the optical axis is reflected back upon itself from the
vertex S. This ray represents a perpendicular. It is marked in with the
whiteboard marker.
Another ray at an angle to the first one reaches the mirror at the vertex S. The
Law of Reflection is demonstrated in this case.





The ray moving along the optical axis is reflected back upon itself. This is called
a midpoint ray since it passes through the center of the circle.
The ray box 1 is used to create a light ray parallel to the axis and reaching the
concave mirror at point P. Being reflected according to the Law of Reflection,
this ray intersects the optical axis at the focal point F1. The reflected light ray
PF1 is drawn in.

12 | Optics Panel Type




A ray of light traveling along the line F1P is reflected parallel to the optical axis.

Optics Panel Type | 13


IMAGES IN A CONCAVE MIRROR
(P 32 09)

Apparatus:
GSN 246
POG 465
POG 461
POG 480.01
POG 101

KAL 60/5A

Adhesive magnetic
board
Ray box, 6V 20 W
Diaphragm 1 and 2 slits
Arrow, L=40 mm
Mirror, flexible
Connecting lead
Power supply
Whiteboard marker

1
2
2
1
1
4
1
1

Procedure:











Draw the optical axis and place the arrow as object G.
Use Ray box 1 to generate a light ray parallel to the optical axis and aimed at
the tip of the object.
The light ray proceeding from ray box 2 is a midpoint ray and it is reflected
back upon itself. The inverted, real image B is drawn where the two reflected
rays intersect. The main ray, B, M and F are all drawn in.
The path of the rays shows how a real but smaller, inverted image is created.

The optical axis and the center of curvature M are drawn in, the concave mirror
is mounted as shown.
An object 2 cm high is drawn in as shown in the figure.
Ray box 1 generates a light ray that travels parallel to the optical axis and is
reflected through the focal point F. The object may be seen to be just beyond
the focal length.
The light ray proceeding from the tip of G is drawn in.
Ray box 2 is used to create a light ray passing through the tip of G and the focal
point F which
travels parallel to the axis after being reflected, in accordance with the Law of
Reflection. The light ray is drawn in beginning from the tip of G. The real but
inverted and magnified image B existswhere the two light rays intersect.

14 | Optics Panel Type










The vertex S and the optical axis are drawn in order to illustrate how a virtual
image is created. The concave mirror is set up as shown in the figure. The
object (G = 2 cm) is drawn in at a distance of 3 cm from the concave mirror.
Proceeding form ray box 1, a light ray parallel to the axis passes through the tip
of object G. The light ray proceeding from G and the reflected ray are drawn in.
Object G is found within the focal length.

Ray box 2 generates a light ray passing through the tip of the object and
reaching the mirror at the vertex S. This light ray is drawn in beginning at G. It
may be observed that the two reflected rays cannot intersect each other. No
real image point arises from the object point and a screen simply shows a light
spot.
When looking in the direction of the reflected light ray, the eye does not
perceive the "bend" in the light ray but rather extends it in a straight line. At
the virtual intersection a virtual image arises which can be seen in the mirror.

Optics Panel Type | 15


MOVEMENT OF RAYS IN A CONVEX
MIRROR
(P 32 10)

Apparatus:
GSN 246

POG 465
POG 462
POG 101
KAL 60/5A

Adhesive magnetic
board
Ray box, 6V 20 W
Diaphragm 3 and 5 slits
Mirror, flexible
Connecting lead
Power supply

1
1
1
1
2
1

Procedure:



The light and the convex mirror are set up according to the figure.
The parallel beam of light is reflected divergently by the convex mirror.



When the diaphragm with three slits is inserted, the light rays are observed to

be reflected.

16 | Optics Panel Type


PATH OF RAYS IN A CONVEX MIRROR
(P 32 11)

Apparatus:
GSN 246
POG 465
POG 461
POG 101
KAL
60/5A

Adhesive magnetic
board
Ray box, 6V 20 W
Diaphragm 1 and 2 slits
Mirror, flexible
Connecting lead
Power supply

1

Whiteboard mareker

1

2
2
1
4
1

Procedure:


The light ray generated by ray box 1 is positioned so that it is reflected upon
itself. It thus serves as a perpendicular. Its extension (to be drawn in) intersects
the extension of the optical axis at the center of curvature M.



Ray box 2 produces a light ray traveling parallel to the axis. It is reflected
according to the Law of Reflection (angle of incidence angle of reflection
). The Law of Reflection is confirmed. A virtual focal point F is created where
the extension of the reflected ray intersects the extension of the optical axis.

Optics Panel Type | 17


PATH OF RAYS WHEN FORMING AN
IMAGE
IN A CONVEX MIRROR
(P 32 12)

Apparatus:
GSN 246

POG 465
POG 461
POG 101
POG 480.01
KAL 60/5A

Adhesive magnetic
board
Ray box, 6V 20 W
Diaphragm 1 and 2
slits
Mirror, flexible
Arrow, L=40 mm
Connecting lead
Power supply
Whiteboard marker

1
2
2
1
1
2
1
1

Procedure:









The optical axis and the vertex are drawn in.
The arrow with l = 40 cm and representing an object is fastened in place.
The convex mirror is put into place.
Ray box 1 generates a ray of light traveling parallel to the axis through the tip
of the object.
The reflected ray and its extension are drawn in.

The light ray proceeding from ray box 2 also passes through the tip of the
object and is reflected by the convex mirror. The incoming ray, the reflected ray
and its extension are drawn in.
The two reflected rays do not intersect. No real image point corresponds to the
object point.
When looking in the direction of the reflected rays' extension, the eye does not
perceive the "bend" in the light's path when it hits the mirror, instead it extends
the reflected rays in a straight line. This causes the impression of an apparently
smaller, upright image behind the surface of the mirror.

18 | Optics Panel Type


Optics Panel Type | 19