Light changes speed as it
enters from one medium to another and bends. The bend of light depends on the
refractive index of the medium. Different mediums have different refractive
index and density.
Refraction
of light is incident ray tilt or light when it passes through two different
media. Refraction of light occurs when light through two different medium
density. As the density of water is greater than the density of air, while air
has a density of more tenuous than the density of the glass. In general there
are two kinds of refraction:
a.Rays coming from the media more more tenuous to the media
that tightly will be refracted near the normal line (i> r)
b.Rays coming from the media more tightly into a more
tenuous medium will be refracted away from the normal line.
These images shows the refraction of light:
The light bends as it passes from air to water.
A prism refracts light at different directions to form a rainbow.
In the
refraction effect of refraction Snell's law, which reads as follows.
1. Rays come, the normal line, and the refraction
ray is located in one plane.
2. Comparison between the projection and
projection ray rays come to the field boundary refraction is a remains
number called the relative refractive index.
The diagram below shows the refraction of light when it passes from one medium
to another. The red line is the normal, which is perpendicular to the surface
of the medium. As the light passes through the second medium, the light bends
towards the normal because density of the second medium is greater than the
first. The angle between the incoming ray and the normal is the angle of
incidence. The angle between the refracted ray and the normal is the angle of
refraction.
Mathematical formulation of Snell's law is :
or
or
The symbolθ1, θ2refers
to theangle of incidenceandrefractionangles, v1 andv2on the speedof lightrays comeandlightrefraction.
The symbolrefers to therefractive indexn1mediumthrough which therays come, whilen2 isthe
refractive index ofthe mediumthrough
whichlightrefraction.
To betterunderstand,try
to seethe videoas an
applicationofrefraction
Light is one of the electromagnetic waves
under certain conditions can behave like a particle and a wave. As a wave,
light can propagate in a straight line, can be reflected, refracted, and
experience the polarization and interference.
1. Reflection of Light
Properties of light waves that we see most
often is the reflection of light.
In pictures: a. Regular
reflection is reflection of light that occurs on a flat surface. For example
the mirror.
b. Diffusereflectanceisthe reflectanceof lightthat occursonuneven surfaces. For examplewallsand wood.
2. Reflection
the mirror on the flat
The statement, known as Snell'slaw ofreflectionof light(rays), are
:
a. Rays come, the normal line, and the reflected rays lie in
one plane.
b. Angle of incidence equal to angle reflection.
Flat mirror will produce regular reflection. Therefore, the image
produced can be described by using the law of Snell's proposed light reflectance.
The properties of the image produced by a plane mirror is virtual, erect and size
as large.
To betterunderstand,try to seethe videoas animageformationbyplane mirror
If two plane mirrors
arranged so that an angle α will be obtained a few shadows. Many of the images
forming between the two mirrors can be expressed in the following equation.
Explanation:
n : many shadow forming
α : angle is flanked by two mirrors
3. Reflection on the concave mirror
Concave mirror is a mirror that has a
reflective surface curved inward. Is convergent or concave mirror to collect
light. Parts of the concave mirror:
Explanation :
a. P : the center of curvature
mirror
b. F : the focus point
c. O : center point of the
mirror surface
d. OF
: focus distance, length is half the radius of curvature of the mirror( f
)
e. OP : The main axis of the
mirror
f. R1, R2, dan R3 :
space
in front of the mirror
g. R4 :
space
behind the mirror
The rays particularconcave mirror:
a. Rays come paralleltothe mainaxisis reflectedthroughthe focus point,
b. Rayscomingthroughthe focal pointis reflected parallel tothe mainaxis, and
c. Rayscomingthrough thecenter ofcurvature of the mirroris reflectedbyraysas well.
To betterunderstand,try
to seethe videoas animageformationbyconcave mirror
The nature of shadow forming the concave mirror can also be determined in the
following ways.
a.Ifs'value
(+)then theimageisreal andinverted, butif s' value(-)
then
theimageisvirtualandupright.
b. If M>
1
thenthe imageis enlarged. If M=1 thenthe imageas large as theobject. If M<1
then the
imageis minimized.
4. Reflection
on the convexmirror
Convex mirror is a mirror that has a curved reflective
surface to the outside. Concave mirror is diverging or spreading of light.
Parts of the convex mirror
Explanation :
a. P :
the
center of curvature mirror
b. F :
the focus point
c. O :
center
point of the mirror surface
d. OF :
focus
distance, length ishalf
the radius of curvature of the mirror( f
)
e. OP :the
main axis of the mirror
The rays particular convex mirror:
a. Rayscomingparallel tothe mainaxisis reflectedas ifcoming fromthe focal point.
