Luminous object is a object that can shining by
itself or emit light by itself.
Example : Fire , sun , lamp.
Non luminous object is a object that cannot
emit light itself they can only reflecting light.
Example : Moon, Table , Chair ,etc.
Light rays is a line of light.
Light travel in all direction.
Line of light can be seen clearly if they travel in
Transparent let light to pass on. Ex: Glass ,
Translucent not let pass some light but pass
some light through them. Ex : Tracing Paper
Opaque not let all light to pass through them.
Ex: wood, metal.
As light cannot pass through opaque object it
will make a dark area usually behind the object
it was called shadows.
Te size of the shadows depends on the light
source and the distance of the light source and
The greater the light source there will be a
shadow that have dark in the middle and grey
The less the light source the darker the shadow
in the middle part.
The further the distance between the object and
the light source will make small shadow.
The shorter the distance between object and
light source it will make a big shadow.
You can see object because the object is
reflecting the light and the reflected light will
be caught by our eye.
Incident ray is a light that strike the surface of
Reflected ray is a light ray that is reflected from
Normal is a line that is perpendicular at 90
degree to the surface where a ray strike.
Angle of incidence is the angle between
incident ray and normal.
Angle of reflection is the angle between
reflection ray and the normal line.
Plane mirror is a mirror with flat surface.
Image is appearance of an object in smooth
When light ray strike a smooth surface the
angle of reflection is equal to the angle of
When reflected light reach your eyes you will
be able to see the image.
Real image is a image that can be projected into
Virtual image is a image you see in a mirror
that are in the same size but only in opposite
Light rays that strike the rough surface will not
have same angle of incidence and angle of
Because of this effect you will not able to see
your image in the rough surface thing.
Refraction is light that is bend because of
different position of object and different
The angle which the ray makes with normal is
called angle of refraction.
Light travel in different speeds in different
If the light slows down it bends toward the
A light ray can appear different direction than
the actual place example stone in water.
Periscope is an equipment made by two plane
If the sun light strikes the prism in certain
angle and stop by a white screen it will make a
range of color is spread out and called as
The sun light contains different color because
have different wave length and travel in
Rainbow are appear because of the refraction
and reflection of the sun light by the water
There can be two rainbow if there is 2 reflection
If all the colors are reflected the color will seem
to have white color
If all colors are absorb the color of the object
will seem black.
Usually object absorb some color and reflected
Because some object reflecting and absorb
some color so if you put blue glass the only
color that can be pass through is blue and the
When different type of light color is mix up it
can make new color. Ex blue and red become
When three beams of light is shining into white
screen it will produce 3 secondary color and