OPTICS
Reflection of light
Describes how the light returns to its original medium as a result of an impact on a surface.
Diffuse reflection
Subtopic
An incident ray of light touches an irregular surface, the ray of light reflected is not well.defined and the light is scattered in all directions.
Law of reflection
The ray of light that touches a surface with one angle of incidence is reflected with one angle of reflection, and these angles are equals and are measured from a line perpendicular to the surface at the point of incidence.
Is a mirror when the surfaces is a smooth and reflects the rays of light received.
Reflected: The ray of light that are repulsed.
Incident: the ray of light that reaches the mirror
If the surfaces is a smooth, the rays are reflected or repulsed in a single direction.
When the light touches the surface of an object is reflected in all directions.
Mirrors
Principal rays in mirrors:
production of images
Main ray
Passes through the center of the curvature, is reflected
along the length of the trajectory of the original ray.
Focal ray
Passes through the focus and is reflected
parallel to the axis of the mirror
Parallel ray to the
axis of the mirror
Is reflected, passes through the focus in
a concave mirror and comes from the
focus of a convex mirror.
Spherical
Focal Point (F)
In which the rays reflected
coincide in the mind point
of the radius of curvature.
Vertex (V)
Center (C)
Radius (R)
Convex
The reflective surface of the
outside part of the mirror is
spherical.
Concave
The surface of the inside part of
a sphere is reflective. Is called
"Convergring mirror".
Plane
Its surfaceis flat,the virtual image is
symetrical in reality and inside the mirror,
since they have the same distance,
the images are the reflections of the objects,
the real image is shaped by true rays of light
that pass through it.
Refraction of light and
total internal reflection
Critical angle
The angle of incidence in which the total internal reflection is characteristic of each medium.
Total internal Reflection
If the angle of incidence is sufficiently large, the refraction can reach 90° and the refracted ray will disappear.
The trajectory of a refracted ray at the surface separating the two mediums is directly reversible.
Index of refraction
In a vacuum or air the refractive index of the medium is the ratio between velocities of light and the speed of light.
n1sinθ1=n2sinθ2
Is for two transparent mediums in which the ratio between the sine of the angle of incidence and the angle of refraction
n= sinθi/sinθrc
Is calculated by the ratio of the speed of light in the first and second medium.
n= sinθi/sinθrc=v1/v2
Lenses
Parts
Focus
The light rays pass parallel to its axis in converging lenses, and in diverging lenses passing through the lens from a beam of parallel ray as they exist the focal point.
Central plane
Is perpendicular to the main axis
Axis
Is the straight line that passes horizontally through the center
Types
Diverging
Refracts and diverges parallel light from a focal point in front of the lens, are thinner at their centers than at their ends, are common for people with myopia.
Converging
Converges and refracts a parallel light a focal point beyond the lens. Are thicker in the center and taper at their ends, they amplify the images.
Characteristics
They can be conceived as a set of prisms they alter the shape of a front of waves passing from one medium to another.
Are used for construct telescopes, photographic cameras,glasses, etc.
Are transparent objects of crystal or plastic limited by two surfaces: spherical and flat
Electromagnetic spectrum
and visible spectrum
Visible
Is only a small part of the electromagnetic spectrum. Is located between the wavelengths of 400nm for UV light and 700nm for infrared. The light that passes through a prism is dispersed, and a band of colors appears: violet,blue, green and brown
Violet light
Is the most refracted and deflected
Wavelength: 400 nm
Frequency: 8x10^14 Hz
Red light
Is a least refracted and deflected
Wavelength: 700 nm
Frequency: 3x10^14 Hz
White light
Is constituted by the superposition of
the colors of the rainbow.
The spectrum of colors that forms white light
in air or in a vacuum have the same speed.
Electromagnetic
Is made up pf the different kinds of electromagnetic radiation in an electric and magnetic field. There are transverse waves. We can see how wavelength decreases progressively beginning with the wave length of short radio waves, infrared, visible light, ultraviolet, X and gamma rays. Each region of the spectrum has its own characteristics
Region of visible light
1nm=10^-9 m=10^-7
General ecuation
c= λf
Velocity propagation of all electromagnetic radiation
300000 km/s in a vacuum.
Speed of light
Albert A. Michelson
Used Folcault's method, which replaced the rotating cogwheel
with a rotating mirror. He obtained accurate measures to determine the speed of light in air.
2.997925x10^8m/s
A.H.L Fizeau
In his experiment, light passes between two teeth on the wheel, then passes through the mirror and back between two other teeth knowing the distance between the wheel and the mirror, the number of teeth, the angular velocity, and the speed of light.
3.13x10^8m/s
Olaus Roemer
Based on the irregularity of the eclipses of Jupiter's moons, and found a variation of 1300s and realized that it was the time it took for light to reach Earth from Jupiter
V=s/t=3x10^11m/1300s=2.31x10^8m/s
Galileo Galilei
It was based on the distance between two towers, from where an observer will send signals with flashlights at night, although he only confirm that the light is transmitted instantaneously
Nature of light
Albert Einstein
He explained the Photoelectric Effect
Max Planck
Explain the radiation emitted by a black body, and proposed
that the thermal energy emitted by a body is presented in "quanta" which are called photons.
Rudolf Hertz
The light presents the phenomena
of reflection, and diffraction.
James Clerk Maxwell
The light is an electromagnetic wave of
high frequency that is displaced in a vacuum.
Jean Foucault
Show that the speed of light through
solid or liquids was slower than air.
Thomas Young
Made the first convincing demostration about the nature
of light upon discovering that, under certain conditions,
light had characteristics of superposition.
Christian Huygens
He formalized the wave theory and demonstrated
the laws of reflection and refraction.
Issac Newton
He could explain the phenomena related to
reflection and refraction by the corpuscular theory.
Descartes
The light was pressure which was propagated
in a dense universe full of particles,and it was
perceived through vibrations.
Leonardo da Vinci
He wrote that the waves of light were separated
from a body, spreading in circles to fill the space
around them.
Epicurus of Samos
The light was emitted in the from of rays,
which upon entering the eye simulated the
the sense of sight.
Aristotle
He considered light as a kind of pulsation
in the ether.
Pythagoras
Pointed out that the light emanates from
luminous bodies in all directions.
Democritus
Believed that the light was composed of a
large number of particles.
What is?
Studies light and the phenomena it produces
Quantum Optics
Light is consider a corpuscle, that is, small particles
that move and impact on objects, making them visible.
Physical Optics
Light is consider as waves, including all
the wave phenomena.
Geometric Optics
Studies the behavior of light propagated
in straight lines called rays.
