LIGHT : Refraction of Lens

Material :

The Refraction Lens

The lens is a transparent object is bounded by two curved area or areas of curved and flat fields. Lenses are of two kinds, namely concave lenses and convex lenses.

a.       Refraction of the concave lens

Concave lens is a lens that is spreading so-called light diverging lens. The radius of curvature of the concave lens is negative.

 

O : lens focal point 
F₁ : focal point of the first concave lens surface
F_{2 :} focal point of the second concave lens

There are several kinds of concave lenses, convex lenses are concave, plan concave lenses, and lens bikonkaf.

 

Concave lens has three special rays which are:

 

(a) major axis parallel rays come, (b) light coming through the optical center, and  (c) rays come into focus point  

The rays Particular are as follows :

                a.  Rays coming parallel to the major axis is refracted as if coming from the focal point.

b.  Rays coming through the optical center will be forwarded without refracted.

c.  Rays will come into focus point is refracted parallel to the main axis.

The equation applies to the concave lens is as follows:    

Magnification on a concave lens can be searched by using the formula:

b.        Refraction of the convex lens

Convex lens  is a lens that collects light that is called a converging lens. In contrast to the concave lens, the radius of curvature of a convex lens is positive .

                   O : lens focal point

                  F₁ : focal point of the first concave lens surface

                   F_{2 :} focal point of the second concave lens

Convex lens there are three kinds, namely convex concave, convex plan, and bikonveks.

 

Convex lens has three particular rays which are:

 

(a) rays coming parallel to the main axis, (b) light coming through the optical center, and (c) light coming through the front of the lens focal

The rays in particular convex lens is as follows:

a. Major axis parallel rays come to be refracted through the focal point.

b. Rays coming through the optical center will be forwarded without refracted.

                c. Rays coming through the front of the lens will focus parallel to the principal axis is refracted.

The equation applies to the convex lens is as follows:

Magnification on a concave lens can be 
searched by using the formula :    
                       
                            

To better understand, try to see the video as the image formation by concave and convex lenses

The Power of Lens

Power of the lens is the ability of a lens to collect light at the lens convex and concave lenses to spread light on. The greater the power of a lens, the greater the lens bend light. Power of the lens can be formulated :

   

Keterangan:

P : the power of lens (dioptri)

f : focusing lens (m)

 

LIGHT : Refraction

Material :

What causes light to refract?

             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 symbol θ1, θ2 refers to the angle of incidence and refraction angles, v1 and v2 on the speed of light rays come and light refraction. The symbol refers to the refractive index n1 medium through which the rays come, while n2 is the refractive index of the medium through which light refraction.

 To better understand, try to see the video as an application of refraction

 

LIGHT : Reflection

 Material :

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. Diffuse reflectance is the reflectance of light that occurs on uneven surfaces. For example walls and wood.

2. Reflection the mirror on the flat

The statement, known as Snell's law of reflection of 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 better understand, try to see the video as an image formation by plane 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 particular concave mirror :

a. Rays come parallel to the main axis is reflected through the focus point,

b. Rays coming through the focal point is reflected parallel to the main axis, and

c. Rays coming through the center of curvature of the mirror is reflected by rays as well.

To better understand, try to see the video as an image formation by concave mirror

The nature of shadow forming the concave mirror can also be determined in the following ways.

a.    If s' value (+) then the image is real and inverted, but if s' value (-) then the image is virtual and upright.

b. If M> 1 then the image is enlarged. If M = 1 then the image as large as the  object. If M <1 then the image is minimized.

4. Reflection on the convex mirror

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 is half  the radius of curvature of the mirror ( f )

e. OP   :the main axis of the mirror

The rays particular convex mirror :

a.  Rays coming parallel to the main axis is reflected as if coming from the focal point.

b. Rays come into the focus point is reflected parallel to the main axis.

c.  Rays come into the center of curvature of the mirror will reflect light coming through.
  

To better understand, try to see the video as an image formation by convex mirror

The nature of images forming the convex mirror has a trait that is virtual, upright, and minimized.

The equation is valid for concave mirrors and convex mirrors are as follows:

  M =                                                       

Explanation:

f           : focusing mirror (cm atau m)

s₀         : distance of objects in the mirror (cm atau m)

s₁         : distance to the mirror image (cm atau m)

R          : the radius(cm atau m)

h₁            : high shadow (cm atau m)

h₀         : high objects (cm atau m)

M         : magnification