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Flash animations for OPTICS learning

 

 

 

Basic Concepts

 

01. Propagation of light | diffusion   

 

02. Light sources | primary vs secondary | diffusion   

 

03. Shadows   

 

04. Moon phases   

 

Colours

 

05. Additive color model   

 

06. Subtractive color model   

 

07- A. Colors of objects 1    

 

07- B. Colors of objects 2    

 

07- C. Colors of objects 3   

 

08. Vive la France !   

 

 

 

 

 

Lens

 

09. Converging lens   

 

10. Camera Focus   

 

Refraction

 

11. Refraction | Snell/Descartes law   

 

12. Scattering by a prism | Emission | Absorption   

 

 

 

 

 

 

 

 

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LIGHT SOURCES AND IMPORTANCE OF RELEASE

 

 

 

Entry of light into the eye

 

Existence of two types of light sources:

- Primary sources (stars, sun ...);

- Scattering objects (planets, satellites, white walls ...).

A necessary condition for vision: the entrance of light into the eye.xistence de deux types de sources de lumière :

 

 

 

Rectilinear propagation of light

 

The light beam.

Model of the light.

Direction of propagation of light.

Own shadow, shadow and shadow cone: interpretation in terms of light rays.

Sun-Earth-Moon

Phases of the Moon, eclipses: simplified interpretation.

 

Colored lights and color of objects

 

First notions of colored lights:

- As a filter;

- Continuous spectrum;

- Superposition of colored lights.

First ideas on the color of objects.

By absorbing light, the matter receives energy. It heats up and transfers part of the energy received from outside the form of heat.
 

 

 

Lenses: homes and pictures

 

Principle of image formation in geometrical optics.

Concentration of energy with the thin lens convergent.

Focal length.

Safety: danger of direct observation of the sun through a converging lens.

Modeling of the eye.

Vision results from the formation of an image on the retina.

Experimental approach to corrections of the defects of the eye (myopia, hyperopia).
 

 

Speed of light and sound, signal propagation

 

- The light can propagate in a vacuum and in transparent media like air, water and glass.
Speed of light in vacuum (3x108 m / s or 300,000 km / s).
Orders of magnitude of distances from Earth to a few stars and galaxies in the Universe or duration of propagation of light corresponding.

- Sound travels in matter media (solid, liquid and gas) and it does not spread into space.
Magnitude of the speed of sound in air: 340 m / s.
Sounds too intense have implications for the hearing.

- A transmitter (light source, sound source, transmitting antenna) transmits a signal that propagates this signal can be received by a receiver (eye, ear, receiving antenna).
The man is surrounded by a multitude of signals that carry information.

 

A dispersive prism
Characterization of radiation.
Descartes' laws of refraction for radiation (one of the media being air).
Dispersion of white light by a prism.
Change in the index of a transparent medium according to the radiation passing through it; qualitative interpretation of the scattering of light by a prism.
 

The emission spectra and absorption.

 

 

Emission spectra
Continuous spectra of thermal origin.
Line spectra.

Absorption spectra
Absorption bands of colored solutions.
Absorption lines characteristic of an atom or ion.

Application to astrophysics

 

Visibility of an object

 

Role of the eye in direct view of objects. Propagation of light: model of the light-no-object.
Converging lenses, diverging lenses. Simple screening criteria.

 

Images formed by optical systems

 

Images provided by a plane mirror

Observation and location of the image of an object given by a plane mirror.
Conjugated image point of an object point. Laws of reflection.

 

Images provided by a converging lens

Observation and location of images given by a convergent lens.
Geometric modeling of a thin lens convergent optical center, fireplaces, focal distance, vergence.
Analytical model: relations conjugation and thin converging lens magnification.
Magnifying glass.

 

An example of optical device

 

Experimental modeling of an optical instrument simple telescope, spotting scope or binoculars, camera projection or rear projection...

 

The light wave model

 

Experimental observation of diffraction in monochromatic light and white light (irization).

 

Wave model of light speed, wavelength in vacuum, frequency :

 λ = c.T = c/ν.

Influence of the size of the aperture or obstacle on the observed phenomenon; angular beam diffracted by a slit or a straight wire of width a :

θ = λ / a.

Monochromatic light, polychromatic light, frequency and color.
Propagation of light in transparent media, index of the medium.
Highlighted the phenomenon of dispersion of white light through a prism: the index of a transparent medium depends on the frequency of light.

 

 

- Produce images, see

 

Formation of an image

Image formed by a converging thin lens

Graphic constructions of the image:
- An object plane perpendicular to the optical axis.
- A point object at infinity.
Conjugation relations in algebraic form, magnification.
Validity of this study : Gauss conditions.

 

Image formed by a converging spherical mirror
Summit, home, principal optical axis, focal length.
Graphic constructions of the image:
- An object plane perpendicular to the principal optical axis.
- A point object at infinity.

 

Some optical instruments

The microscope

Brief description and role of each component: condenser (spherical mirror), objective eye.
Modeling a system of two thin lenses:
- Graphical construction of the intermediate image and the image of an object plane perpendicular to the optical axis.
- Characteristics of the intermediate image and final image by building and / or application forms of conjugation.
- Apparent diameter.
- Standard magnification.
- Eye-ring.

 

Telescope and Newtonian one

Brief description and role of each component :
- Telescope : objective eye.
- Newtonian : spherical mirror, plane mirror target.
Modeling of the telescope by an afocal system of two thin lenses and modeling of a Newton telescope with a mirror system, thin lenses :
- Graphical construction of the intermediate image and the image of an object plane perpendicular to the optical axis.
- Characteristics of the intermediate image and final image by building and / or application forms of conjugation.
- Apparent diameter.
- Standard magnification.
- Eye-ring.