Here are abstracts on physics on the topic "Optics" for grades 10-11.
!!! Notes with the same title differ in degree of difficulty.

3. Diffraction of light- Wave optics

4. Mirrors and lenses- Geometric optics

5. Light interference- Wave optics

6. Light polarization- Wave optics

Optics, geometric optics, wave optics, grade 11, abstracts, abstracts in physics.

ABOUT COLOR. DID YOU KNOW?

Did you know that a piece of red glass appears red in both reflected and transmitted light. But for non-ferrous metals, these colors differ - for example, gold reflects mainly red and yellow rays, but a thin translucent gold plate transmits green light.

Scientists of the 17th century did not consider color to be an objective property of light. For example, Kepler believed that color is a quality that philosophers, not physicists, should study. And only Descartes, although he could not explain the origin of colors, was convinced of the existence of a connection between them and the objective characteristics of light.

The wave theory of light created by Huygens was a great step forward - for example, it gave the explanations of the laws of geometric optics that are still used today. However, its main failure was the absence of a color category, i.e. it was the theory of colorless light, despite the discovery already made by that time by Newton - the discovery of the dispersion of light.

The prism - the main instrument in Newtonian experiments - was bought by him in a pharmacy: in those days, the observation of prismatic spectra was a common pastime.

Many of Newton's predecessors believed that colors originated in the prisms themselves. Thus, Newton's constant opponent Robert Hooke thought that a sunbeam could not contain all colors; it was as strange, he thought, as to say that "all tones are contained in the air of organ bellows."

Newton's experiments led him to a sad conclusion: in complex devices with a large number of lenses and prisms, the decomposition of white light is accompanied by the appearance of a mottled color border on the image. The phenomenon, called "chromatic aberration", was subsequently overcome by combining several layers of glass with "balancing" each other's refractive indices, which led to the creation of achromatic lenses and telescopes with clear images without color reflections and bands.

The idea that color is determined by the frequency of vibrations in a light wave was first expressed by the famous mathematician, mechanic and physicist Leonhard Euler in 1752, with the maximum wavelength corresponding to red rays, and the minimum to violet.

Initially, Newton distinguished only five colors in the solar spectrum, but later, striving for a correspondence between the number of colors and the number of fundamental tones of the musical scale, he added two more. Perhaps this was an addiction to the ancient magic of the number "seven", according to which there were seven planets in the sky, and therefore there were seven days in a week, in alchemy - seven basic metals, and so on.

Goethe, who considered himself an outstanding naturalist and a mediocre poet, ardently criticizing Newton, noted that the properties of light revealed in his experiments were not true, since the light in them was "tortured by various instruments of torture - slits, prisms, lenses." True, quite serious physicists later saw in this criticism a naive anticipation of the modern point of view on the role of measuring equipment.

The theory of color vision - about obtaining all colors by mixing the three main ones - originates from Lomonosov's speech of 1756 "The word about the origin of light, presenting a new theory about colors ...", which, however, was not noticed by the scientific world. Half a century later, this theory was supported by Jung, and in the 1860s his assumptions were developed in detail into a three-component color theory by Helmholtz.

If any pigments are absent in the photoreceptors of the retina, then the person does not feel the corresponding tones, i.e. becomes partially colorblind. Such was the English physicist Dalton, after whom this lack of vision is named. And it was discovered by Dalton by none other than Jung.

The phenomenon, called the Purkyne effect - in honor of the famous Czech biologist who studied it, shows that different media of the eye have unequal refraction, and this explains the occurrence of some visual illusions.

The optical spectra of atoms or ions are not only a rich source of information about the structure of the atom, they also contain information about the characteristics of the atomic nucleus, primarily related to its electric charge.

Shemyakov N. F.

Physics. Part 3. Wave and quantum optics, the structure of the atom and the nucleus, the physical picture of the world.

The physical foundations of wave and quantum optics, the structure of the atom and the nucleus, the physical picture of the world are outlined in accordance with the program of the general course of physics for technical universities.

Particular attention is paid to the disclosure of the physical meaning, the content of the main provisions and concepts of statistical physics, as well as the practical application of the phenomena under consideration, taking into account the conclusions of classical, relativistic and quantum mechanics.

It is intended for students of the 2nd year of distance learning, can be used by full-time students, graduate students and teachers of physics.

Cosmic showers streamed from the sky, Carrying streams of positrons on the tails of comets. Mesons, even bombs appeared, There are no resonances there ...

7. WAVE OPTICS

1. The nature of light

According to modern ideas, light has a corpuscular nature. On the one hand, light behaves like a stream of particles - photons, which are emitted, propagated and absorbed in the form of quanta. The corpuscular nature of light is manifested, for example, in the phenomena

photoelectric effect, Compton effect. On the other hand, light has wave properties. Light is electromagnetic waves. The wave nature of light is manifested, for example, in the phenomena interference, diffraction, polarization, dispersion, etc. Electromagnetic waves are

transverse.

AT electromagnetic wave, the vectors oscillate

electric field E and magnetic field H , and not matter, as, for example, in the case of waves on water or in a stretched cord. Electromagnetic waves propagate in vacuum at a speed of 3,108 m/s. Thus, light is a real physical object that is not reduced to either a wave or a particle in the usual sense. Waves and particles are just two forms of matter in which the same physical entity is manifested.

7.1. Elements of geometric optics

7.1.1. Huygens principle

	When waves propagate in a medium, including
	number and electromagnetic, to find a new
	wave front at any time
	use the Huygens principle.
	Each point of the wave front is
	source of secondary waves.
	In a homogeneous isotropic medium, wave
	surfaces of secondary waves have the form of spheres
	radius v t,	where v is the propagation velocity
	waves in the medium.	Passing the envelope of the wave

fronts of secondary waves, we get a new wave front at a given time (Fig. 7.1, a, b).

7.1.2. Law of reflection

Using the Huygens principle, one can prove the law of reflection of electromagnetic waves at the interface between two dielectrics.

The angle of incidence is equal to the angle of reflection. The incident and reflected rays, together with the perpendicular to the interface between two dielectrics, lie in

to SD is called the angle of incidence. If at a given time the front of the incident wave OB reaches point O, then, according to the Huygens principle, this point

begins to radiate a secondary wave. During		t = BO1 /v incident beam 2
	reaches point O1. During the same time, the front of the secondary
	waves, after reflection in t. O, propagating in
	the same environment, reaches the points of the hemisphere,
	radius OA = v	t = BO1 .New wave front
	depicted by the plane AO1, and the direction
	dissemination	beam OA. Angle called
	reflection angle. From the equality of triangles
	OBO1 and OBO1 follow the law of reflection: angle
	incidence is equal to the angle of reflection.

	7.1.3. Law of refraction
	An optically homogeneous medium 1 is characterized by an absolute
refractive index
	speed of light in vacuum; v1		the speed of light in the first medium.
where v2
	Attitude	n2 / n1 = n21

is called the relative refractive index of the second medium relative to the first.

frequencies. If the speed of light propagation in the first medium is v1, and in the second v2,

medium (in accordance with the Huygens principle), reaches the points of the hemisphere, the radius of which is OB = v2 t. The new front of the wave propagating in the second medium is represented by the plane BO1 (Fig. 7.3), and its direction

propagation by rays OB and O1 C (perpendicular to the wave front). The angle between the OB beam and the normal to the interface between two dielectrics in

point O called the angle of refraction. From triangles OAO1

GBO1

it follows that AO1 = OO1 sin

OB = OO1 sin .

Their attitude expresses the law

refraction (Snell's law):

n21.

The ratio of the sine of the angle of incidence to the sine of the angle

refraction

relative

the refractive index of the two media.

7.1.4. Total internal reflection

According to the law of refraction at the interface between two media, one can

observe total internal reflection, if n1 > n2 , i.e.

7.4). Therefore, there is such a limiting angle of incidence

pr when

900 . Then the law of refraction

takes the following form:

sin pr \u003d

(sin 900=1)

With further

increase

fully

reflected from the interface between two media.

Such a phenomenon is called total internal reflection and are widely used in optics, for example, to change the direction of light rays (Fig. 7. 5, a, b). It is used in telescopes, binoculars, fiber optics and other optical instruments. In classical wave processes, such as the phenomenon of total internal reflection of electromagnetic waves,

phenomena similar to the tunnel effect in quantum mechanics are observed, which is associated with the corpuscular-wave properties of particles. Indeed, during the transition of light from one medium to another, refraction of light is observed, associated with a change in the speed of its propagation in various media. At the interface between two media, a beam of light is divided into two: refracted and reflected. According to the law of refraction, we have that if n1 > n2, then at > pr, total internal reflection is observed.

Why is this happening? The solution of Maxwell's equations shows that the intensity of light in the second medium is different from zero, but very quickly, exponentially, decays with distance from

	section boundaries.
		experimental
	observation			internal
	reflection is shown in fig. 7.6,
	demonstrates			penetration
	light into the area "forbidden",
	geometric optics.
				rectangular

of an isosceles glass prism, a ray of light falls perpendicularly and, without being refracted, falls on face 2, total internal reflection is observed,

/2 from face 2 to place the same prism, then the beam of light will pass through face 2* and exit the prism through face 1* parallel to the beam incident on face 1. The intensity J of the transmitted light flux decreases exponentially with an increase in the gap h between the prisms according to the law:

Therefore, the penetration of light into the "forbidden" region is an optical analogy of the quantum tunneling effect.

The phenomenon of total internal reflection is indeed complete, since in this case all the energy of the incident light is reflected at the interface between two media than when reflected, for example, from the surface of metal mirrors. Using this phenomenon, one can trace another

analogy between refraction and reflection of light, on the one hand, and Vavilov-Cherenkov radiation, on the other hand.

7.2. WAVE INTERFERENCE

7.2.1. The role of the vectors E and H

In practice, several waves can propagate simultaneously in real media. As a result of the addition of waves, a number of interesting phenomena are observed: interference, diffraction, reflection and refraction of waves etc.

These wave phenomena are characteristic not only for mechanical waves, but also for electric, magnetic, light, etc. All elementary particles also exhibit wave properties, which has been proven by quantum mechanics.

One of the most interesting wave phenomena, which is observed when two or more waves propagate in a medium, is called interference. Optically homogeneous medium 1 is characterized by

absolute refractive index
	speed of light in vacuum; v1 is the speed of light in the first medium.
Medium 2 is characterized by the absolute refractive index
where v2	the speed of light in the second medium.
Attitude

is called the relative refractive index of the second medium

	using Maxwell's theory, or
	where 1 , 2 are the permittivities of the first and second media.
	For vacuum n = 1. Due to the dispersion (frequencies of light				1014 Hz), for example,

for water, n = 1.33, and not n = 9 (= 81), as follows from electrodynamics for low frequencies. Light electromagnetic waves. Therefore, electromagnetic

the field is determined by the vectors E and H , which characterize the strengths of the electric and magnetic fields, respectively. However, in many processes of interaction of light with matter, such as the effect of light on the organs of vision, photocells and other devices,

the decisive role belongs to the vector E, which in optics is called the light vector.

All processes occurring in devices under the influence of light are caused by the action of the electromagnetic field of a light wave on charged particles that make up atoms and molecules. In these processes, the main role

electrons play because of the high frequency

hesitation

light

15 Hz).

current

to an electron from

electromagnetic field,

F qe ( E

0 },

where q e

electron charge; v

his speed;

magnetic permeability

environment;

magnetic constant.

The maximum value of the modulus of the cross product of the second

term at v

H , taking into account

0 H2 =

0 Е2 ,

it turns out

0 N ve =

ve E

the speed of light in

matter and in vacuum, respectively;

0 electric

constant;

the dielectric constant of a substance.

Moreover, v >>ve , since the speed of light in matter v

108 m/s, a speed

an electron in an atom ve

106 m/s. It is known that

cyclic frequency; Ra

10 10

the size of the atom plays a role

amplitudes of forced vibrations of an electron in an atom.

Hence,

F ~ qe E , and the main role is played by the vector

E , not

vector H . The results obtained are in good agreement with the experimental data. For example, in Wiener's experiments, the area of ​​blackening of a photographic emulsion under

by the action of light coincide with the antinodes of the electric vector E .

7.3. Conditions for maximum and minimum interference

The phenomenon of superposition of coherent light waves, as a result of which the alternation of amplification of light at some points in space and attenuation at others is observed, is called light interference.

Necessary condition light interference is coherence

stacked sine waves.

Waves are called coherent if the phase difference of the added waves does not change with time, i.e. = const.

This condition is satisfied by monochromatic waves, i.e. waves

E , folded electromagnetic fields were performed along the same or close directions. In this case, there should be a match

only vectors E , but also H , which will be observed only if the waves propagate along the same straight line, i.e. are equally polarized.

Let us find the conditions for maximum and minimum interference.

To do this, consider the addition of two monochromatic, coherent light waves of the same frequency (1 \u003d 2 \u003d), having equal amplitudes (E01 \u003d E02 \u003d E0), oscillating in vacuum in one direction according to the sine (or cosine) law, i.e.

				E01 sin(				01),
				E02 sin(				02),
where r1 , r2	distances from sources S1 and S2				to the point of observation on the screen;
01, 02	initial phases; k =			wave number.

According to the principle of superposition (established Leonardo da Vinci) the intensity vector of the resulting oscillation is equal to the geometric sum of the intensity vectors of the added waves, i.e.

E2.

For simplicity, we assume that the initial phases of the added waves

are equal to zero, i.e. 01 =

02 = 0. In absolute value, we have

E \u003d E1 + E2 \u003d 2E0 sin [

k(r1

k(r2

In (7.16) the expression

r1 n =

optical path difference

folded waves; n

absolute refractive index of the medium.

For other media than vacuum, for example, for water (n1 , 1 ),

glasses (n2 , 2 ) etc. k = k1 n1 ;

k = k2 n2 ;

1 n1 ;

2n2;

is called the amplitude of the resulting wave.

The amplitude of the wave power is determined (for a unit surface of the wave front) the Poynting vector, i.e. modulo

0 Е 0 2 cos2 [

k(r2

where П = с w,

0E2

volumetric

density

electromagnetic field (for vacuum

1), i.e. P = s

0 E2 .

If J= P

the intensity of the resulting wave, and

J0 = with

0 E 0 2

its maximum intensity, then taking into account

(7.17) and (7.18) intensity

of the resulting wave will change according to the law

J = 2J0 (1+ cos).

Phase difference of the added waves

and does not depend on the time

2 = tkr2 +

1 = t kr1 +

The amplitude of the resulting wave is found by the formula

K(r2

r1 )n =

Two cases are possible:

1. Maximum condition.

If the phase difference of the added waves is equal to an even number

	1, 2, ... , then the resulting amplitude will be maximum,
	E 02 E 012 E 022 2E 01E 02
	E0 \u003d E01 + E02.
Therefore, the wave amplitudes add up,		and when they are equal
(E01 = E02)	the resulting amplitude is doubled.
The resulting intensity is also maximum:
	Jmax = 4J0 .