One of the main provisions of geometric optics states that light rays are semi-direct rays emanating from the point of their distribution - the so-called light source. The physical nature of light is not discussed in this definition, but only a certain mathematical picture is given. It is stipulated that the light beam does not change its direction if the characteristics of the medium in which the light propagates remain low. What happens if these properties change? For example, will they change abruptly, what happens at the boundary of the intersection of two environments?
Direct observations show that some of the light rays change their direction as if they were being reflected from the boundary. An analogy can be drawn with a billiard ball: when it collides with the wall of a billiard table, the ball is reflected from it. Then the ball moves in a straight line again, until the next collision. The same thing happens with rays of light, which gave medieval scientists reason to talk about the corpuscular nature of light. Newton, for example, adhered to the corpuscular model of light. This phenomenon is called “light reflection”. The figure below shows it schematically:
We encounter reflections of light everywhere. Beautiful pictures on the surface of the water surface are formed precisely due to the reflection of light rays from the water surface:
But the most important thing: if this phenomenon were not in nature, we would not see anything at all, and not just these highly artistic plans. After all, we do not see objects, but rays of light reflected from these objects and directed at the retina of our eye.
Law of Light Reflection
It is not enough for physicists to know about the existence of this or that natural phenomenon - it must be described precisely, that is, in the language of mathematics. How exactly is a light beam reflected from a surface? Since light travels in a straight line both before and after reflection, to accurately describe this phenomenon we only need to know the relationship between the angle of incidence and the angle of reflection. This relationship exists: “The angle of incidence is equal to the angle of reflection.”
If light falls on a very smooth surface, like the surface of water or the surface of a mirror, then all rays incident at the same angle are reflected from the surface in the same direction - at an angle equal to the angle of incidence. That is why a mirror so accurately conveys the shape of the objects reflected in it. If the surface is rough, then (as in the first figure) then such a pattern is not observed - then they talk about diffuse reflection.
When a light beam falls on the interface between two media, light is reflected: the beam changes the direction of its travel and returns to the original medium.
In Fig. 4.2 shows the incident ray AO, the reflected ray OB, as well as the perpendicular OC drawn to the reflecting surface KL at the point of incidence O.
Rice. 4.2. Law of Reflection
The angle AOC is called the angle of incidence. Please note and remember: the angle of incidence is measured from the perpendicular to the reflective surface, and not from the surface itself! Similarly, the angle of reflection is the angle BOC formed by the reflected ray and the perpendicular to the surface.
4.2.1 Law of reflection
Now we will formulate one of the most ancient laws of physics. It was known to the Greeks back in antiquity!
Law of reflection.
1) The incident ray, the reflected ray and the perpendicular to the reflecting surface drawn at the point of incidence lie in the same plane.
2) The angle of reflection is equal to the angle of incidence.
Thus, \AOC = \BOC, as shown in Fig. 4.2.
The law of reflection has one simple but very important geometric consequence. Let's look at fig. 4.3. Let a light ray emanate from point A. Let's construct a point A0 symmetrical to point A relative to the reflecting surface KL.
Rice. 4.3. The reflected ray leaves point A0
From the symmetry of points A and A0 it is clear that \AOK = \A0 OK. Also, \AOK + \AOC = 90 . Therefore, \A0 OB = 2(\AOK + \AOC) = 180, and, therefore, points A0, O and B lie on the same line! The reflected ray OB seems to come out of point A0, symmetrical to point A
relative to the reflective surface. This fact It will be extremely useful to us in the very near future.
The law of reflection describes the path of individual light rays of narrow beams of light. But in many cases the beam is quite wide, that is, it consists of many parallel rays. The reflection pattern of a wide beam of light will depend on the properties of the reflecting surface.
If the surface is uneven, then after reflection the parallelism of the rays will be disrupted. As an example in Fig. Figure 4.4 shows reflection from a wavy surface. The reflected rays, as we see, go in a variety of directions.
Rice. 4.4. Reflection from a wavy surface
But what does an “uneven” surface mean? What surfaces are “flat”? The answer is: a surface is considered uneven if the size of its unevenness is not less than the length of light waves. So, in Fig. 4.4, the characteristic size of the irregularities is several orders of magnitude greater than the wavelengths of visible light.
A surface with microscopic irregularities comparable to the wavelengths of visible light is called matte. As a result of the reflection of a parallel beam from a matte surface, scattered light is obtained; the rays of such light go in all possible directions3. The reflection itself from a matte surface is therefore called scattered or diffuse4.
If the size of surface irregularities is less than the wavelength of light, then such a surface is called a mirror surface. When reflected from a mirror surface, the parallelism of the beam is maintained: the reflected rays also run parallel (Fig. 4.5).
Rice. 4.5. Reflection from a mirror surface
Approximately mirror-like is the smooth surface of water, glass or polished metal. Reflection from a mirror surface is called specular, respectively. We will be interested in a simple but important special case of specular reflection - reflection in a plane mirror.
4.2.2 Plane mirror
A plane mirror is a part of a plane that specularly reflects light. A flat mirror is a common thing; There are several such mirrors in your home. But now we can figure out why, when you look in the mirror, you see a reflection of yourself and the objects next to you.
Point light source S in Fig. 4.6 emits rays in different directions; let's take two close rays falling on a plane mirror. We already know that reflected rays
3 This is why we see surrounding objects: they reflect scattered light, which we observe from any angle.
4 The Latin word di usio just means spreading, spreading, scattering.
will go as if they were coming from point S0, symmetrical to point S relative to the plane of the mirror.
Rice. 4.6. Image of a light source in a plane mirror
The most interesting thing begins when the diverging reflected rays enter our eye. The peculiarity of our consciousness is that the brain completes the diverging beam, continuing it behind the mirror until it intersects at point S0. It seems to us that the reflected rays come from point S0; we see a luminous point there!
This point serves as an image of the light source S. Of course, in reality, nothing glows behind the mirror, no energy is concentrated there; it is an illusion, an optical illusion, a creation of our consciousness. Therefore, point S0 is called an imaginary image of the source S. At point S0, it is not the light rays themselves that intersect, but their mental continuations “through the looking glass.”
It is clear that the image S0 will exist regardless of the size of the mirror and whether the source is located directly above the mirror or not (Fig. 4.7). It is only important that the rays reflected from the mirror enter the eye, and the eye itself will form an image of the source.
Rice. 4.7. The source is not above the mirror: the image is still there
The location of the source and the size of the mirror determine the field of vision - the spatial area from which the image of the source is visible. The viewing area is defined by the edges K and L of the mirror KL. The construction of the viewing area of the image S0 is clear from Fig. 4.8; the desired vision area is highlighted with a gray background.
Everything we see in the surrounding space either emits light or reflects it.
Emitted Color
is the light emitted by an active source. Examples of such sources include the sun, a light bulb, or a monitor screen. Their action is usually based on heating metal bodies or chemical or thermonuclear reactions. The color of any emitter depends on spectral composition radiation. If the source emits light waves throughout the entire visible range, its color will be perceived by our eyes as white. The predominance of wavelengths of a certain range in its spectral composition (for example, 400 - 450 nm) will give us a feeling of the dominant color in it (in this case, blue-violet). And finally, the presence in the emitted light of light components from different regions of the visible spectrum (for example, red and green) gives us the perception of the resulting color (in this case, yellow). But in any case, the emitted color entering our eye retains all the colors from which it was created.
Reflected light
occurs when some object (or rather, its surface) reflects light waves incident on it from a light source. The mechanism of color reflection depends on the color type of the surface, which can be divided into two groups:
· achromatic;
· chromatic.
The first group consists of achromatic (otherwise colorless) colors: black, white and all grays (from the darkest to the lightest) (Fig. 4). They are often called neutral. In the limiting case, such surfaces either reflect all the rays incident on them without absorbing anything (ideal white surface), or completely absorb the rays without reflecting anything (ideal black surface). All other options (gray surfaces) uniformly absorb light waves of different lengths. The color reflected from them does not change its spectral composition, only its intensity changes.
The second group consists of surfaces painted in chromatic colors, which reflect light differently at different wavelengths. So, if you shine a white light on a piece of green paper, the paper will appear green because its surface absorbs all light waves except the green component. white. What happens if you illuminate green paper with red or blue light? The paper will be perceived as black because the red and blue colors it doesn't reflect. If you illuminate a green object with green light, this will make it stand out against the background of objects of a different color surrounding it.
The process of light reflection is accompanied not only by the associated process of absorption in the surface layer. In the presence of translucent objects, part of the incident light passes through them (see Fig. 4). The action of camera filters is based on this property, cutting out the desired color range from the visible spectrum (in other words, cutting off the unwanted color spectrum).
Rice. 4 Mechanisms of reflection by surfaces: a – green, b – yellow, c-white, d – black surfaces
To better understand this effect, press a piece of colored plexiglass onto the surface of a light bulb. As a result, our eye will “see” the color that is not absorbed by the plastic.
Each object has spectral characteristics of reflection and transmission. These characteristics determine how an object reflects and transmits light at certain wavelengths (Figure 5).
Spectral reflectance curve
determined by measuring the reflected light when an object is illuminated by a standard source.
Personal and psychological factors of drug addiction
In psychology, an attempt was made to build a “specific profile” of a person predisposed to drug use. Research undertaken in this direction is very contradictory. It is believed that the most vulnerable age is adolescence, characterized as a crisis, and therefore vulnerable...
Social and psychological climate in the team
The professional maturity of the team is characterized by another important factor- the socio-psychological climate that has developed in a particular work team. Relationships in a team, its cohesion largely depend on what the members of the team themselves are like, what their personal qualities and general culture...
Shyness is a manifestation of self-doubt.
Fear of failure, fear of people. What is this if not a lack of self-confidence? This means that shyness is born from a person’s lack of self-confidence. What is the difference between a confident person and an insecure person? A self-confident person knows that he has certain rights, knows how and can accurately define and express in such a way that no matter what it affects...
Laws of reflection and refraction of light. Total internal reflection of light
The laws of light reflection were discovered experimentally in the 3rd century BC by the ancient Greek scientist Euclid. Also, these laws can be obtained as a consequence of Huygens’ principle, according to which every point in the medium to which a disturbance has reached is a source of secondary waves. The wave surface (wave front) at the next moment is a tangent surface to all secondary waves. Huygens' principle is purely geometric.
A plane wave falls on the smooth reflective surface of a CM (Fig. 1), that is, a wave whose wave surfaces are stripes.
Rice. 1 Huygens' construction.
A 1 A and B 1 B are the rays of the incident wave, AC is the wave surface of this wave (or the wave front).
Bye wave front from point C will move in time t to point B, from point A a secondary wave will spread across the hemisphere to a distance AD = CB, since AD = vt and CB = vt, where v is the speed of wave propagation.
The wave surface of the reflected wave is a straight line BD, tangent to the hemispheres. Further, the wave surface will move parallel to itself in the direction of the reflected rays AA 2 and BB 2.
Right TrianglesΔАСВ and ΔADB have a common hypotenuse AB and equal legs AD = CB. Therefore they are equal.
Angles CAB = α and DBA = γ are equal because they are angles with mutually perpendicular sides. And from the equality of triangles it follows that α = γ.
From Huygens' construction it also follows that the incident and reflected rays lie in the same plane with the perpendicular to the surface restored at the point of incidence of the ray.
The laws of reflection are valid when light rays travel in the opposite direction. Due to the reversibility of the path of light rays, we have that a ray propagating along the path of the reflected one is reflected along the path of the incident one.
Most bodies only reflect the radiation incident on them, without being a source of light. Illuminated objects are visible from all sides, since light is reflected from their surface in different directions, scattering.
This phenomenon is called diffuse reflection or diffuse reflection. Diffuse reflection of light (Fig. 2.) occurs from all rough surfaces. To determine the path of the reflected ray of such a surface, a plane tangent to the surface is drawn at the point of incidence of the ray, and the angles of incidence and reflection are constructed in relation to this plane.
Rice. 2. Diffuse reflection of light.
For example, 85% of white light is reflected from the surface of snow, 75% from white paper, 0.5% from black velvet. Diffuse reflection of light does not cause unpleasant sensations in the human eye, unlike specular reflection.
Specular reflection of light– this is when light rays falling on a smooth surface at a certain angle are reflected predominantly in one direction (Fig. 3.). The reflective surface in this case is called mirror(or mirror surface). Mirror surfaces can be considered optically smooth if the size of irregularities and inhomogeneities on them does not exceed the light wavelength (less than 1 micron). For such surfaces, the law of light reflection is satisfied.
Rice. 3. Specular reflection of light.
Flat mirror is a mirror whose reflecting surface is a plane. A flat mirror makes it possible to see objects in front of it, and these objects appear to be located behind the mirror plane. In geometric optics, each point of the light source S is considered the center of a diverging beam of rays (Fig. 4.). Such a beam of rays is called homocentric. The image of point S in an optical device is the center S’ of a homocentric reflected and refracted beam of rays in various media. If light scattered by the surfaces of various bodies falls on a flat mirror, and then, reflected from it, falls into the eye of the observer, then images of these bodies are visible in the mirror.
Rice. 4. Image created using a plane mirror.
The image S’ is called real if the reflected (refracted) rays of the beam intersect at point S 1. The image S 1 is called imaginary if it is not the reflected (refracted) rays themselves that intersect in it, but their continuations. Light energy does not reach this point. In Fig. Figure 4 shows an image of a luminous point S, which appears using a flat mirror.
Beam SO falls on the CM mirror at an angle of 0°, therefore, the angle of reflection is 0°, and this ray, after reflection, follows the path OS. From the entire set of rays falling from point S onto a flat mirror, we select the ray SO 1.
The SO 1 beam falls on the mirror at an angle α and is reflected at an angle γ (α = γ). If we continue the reflected rays behind the mirror, they will converge at point S 1, which is a virtual image of point S in a plane mirror. Thus, it seems to a person that the rays are coming out of point S 1, although in fact there are no rays leaving this point and entering the eye. The image of point S 1 is located symmetrically to the most luminous point S relative to the CM mirror. Let's prove it.
Beam SB incident on the mirror at an angle of 2 (Fig. 5.), according to the law of light reflection, is reflected at an angle of 1 = 2.
Rice. 5. Reflection from a flat mirror.
From Fig. 1.8 you can see that angles 1 and 5 are equal – like vertical ones. The sums of the angles are 2 + 3 = 5 + 4 = 90°. Therefore, angles 3 = 4 and 2 = 5.
Right triangles ΔSOB and ΔS 1 OB have a common leg OB and equal acute angles 3 and 4, therefore, these triangles are equal in side and two angles adjacent to the leg. This means that SO = OS 1, that is, point S 1 is located symmetrically to point S relative to the mirror.
In order to find the image of an object AB in a flat mirror, it is enough to lower perpendiculars from the extreme points of the object onto the mirror and, continuing them beyond the mirror, set aside a distance behind it equal to the distance from the mirror to extreme point object (Fig. 6.). This image will be imaginary and in life size. The dimensions and relative position of objects are preserved, but at the same time in the mirror the left and right side the image changes places compared to the object itself. The parallelism of light rays incident on a flat mirror after reflection is also not violated.
Rice. 6. Image of an object in a flat mirror.
In technology, mirrors with a complex curved reflecting surface, for example, spherical mirrors, are often used. Spherical mirror- this is the surface of the body, having the shape of a spherical segment and specularly reflecting light. The parallelism of rays when reflected from such surfaces is violated. The mirror is called concave, if the rays are reflected from inner surface spherical segment.
Parallel light rays, after reflection from such a surface, are collected at one point, which is why a concave mirror is called collecting. If the rays are reflected from the outer surface of the mirror, then it will convex. Parallel light rays are scattered in different sides, That's why convex mirror called dispersive.
| Refraction At the interface between two media, the incident light flux is divided into two parts: one part is reflected, the other is refracted. | |
| V. Snell (Snellius) before H. Huygens and I. Newton in 1621 experimentally discovered the law of refraction of light, but did not receive a formula, but expressed it in the form of tables, because by this time in mathematics were not yet known functions sin and cos. | |
| The refraction of light obeys the law: 1. The incident beam and the refracted beam lie in the same plane with the perpendicular established at the point of incidence of the beam to the interface between the two media. |  |
 | |
| 2. The ratio of the sine of the angle of incidence to the sine of the angle of refraction for two given media is a constant value (for monochromatic light). | |
| The reason for refraction is the difference in the speed of propagation of waves in different media. | |
The value equal to the ratio of the speed of light in a vacuum to the speed of light in a given medium is called the absolute refractive index of the medium. This tabular value is a characteristic of a given environment.  | |
| Proof of the law of refraction. |
 |
 | |
| Propagation of incident and refracted rays: MM" - the interface between two media. Rays A 1 A and B 1 B - incident rays; α - angle of incidence; AC - wave surface at the moment when ray A 1 A reaches the interface between the media. Using Using the Huygens principle, we will construct the wave surface at the moment when the ray B 1 B reaches the interface between the media. We will construct the refracted rays AA 2 and BB 2. β is the angle of refraction AB - the common side of the triangles ABC and ABD. are perpendicular, then angle ABD= α and angle BAC=β Then we get: |   |
| In a prism or plane-parallel plate, refraction occurs on each face in accordance with the law of light refraction. Don't forget that there is always a reflection. In addition, the actual path of the rays depends on both the refractive index and the refracting angle - the angle at the apex of the prism.) |  |
|
 |
||
Total reflection If light falls from an optically denser medium to an optically less dense one, then at a certain angle of incidence for each medium, the refracted beam disappears. Only refraction is observed. This phenomenon is called total internal reflection.  |  |
|
| The angle of incidence, which corresponds to a refraction angle of 90°, is called the limiting angle of total internal reflection (a 0). | ||
| From the law of refraction it follows that when light passes from any medium into vacuum (or air) If we try to look from under the water at what is in the air, then at a certain angle at which we look, we can see the bottom reflected from the surface of the water. This is important to take into account in order not to lose orientation. In jewelry, the cutting of stones is selected so that on each face there is an | ||
| total reflection |  |
|
. This explains the “game of stones”.
The phenomenon of mirage is also explained by total internal reflection.
The law of reflection was first mentioned in Euclid's Catoptrics, dating from around 300 BC. e.
This law is a consequence of the application of Fermat's principle to a reflecting surface and, like all laws of geometric optics, is derived from wave optics. The law is valid not only for perfectly reflective surfaces, but also for the boundary of two media that partially reflects light. In this case, like the law of refraction of light, it does not state anything about the intensity of reflected light.
Reflection mechanism
When hit electromagnetic wave a current arises on the conducting surface, the electromagnetic field of which tends to compensate for this effect, which leads to almost complete reflection of light.
Types of reflection
The reflection of light can be mirrored(that is, as observed when using mirrors) or diffuse(in this case, upon reflection, the path of the rays from the object is not preserved, but only the energy component of the light flux) depending on the nature of the surface.
Mirror O. s. distinguished by a certain relationship between the positions of the incident and reflected rays: 1) the reflected ray lies in the plane passing through the incident ray and the normal to the reflecting surface; 2) the angle of reflection is equal to the angle of incidence j. The intensity of reflected light (characterized by the reflection coefficient) depends on j and the polarization of the incident beam of rays (see Polarization of Light), as well as on the ratio of the refractive indices n2 and n1 of the 2nd and 1st media. This dependence (for a reflecting medium - a dielectric) is expressed quantitatively by the Fresnel formula. From them, in particular, it follows that when light is incident normal to the surface, the reflection coefficient does not depend on the polarization of the incident beam and is equal to
(n2 - n1)²/(n2 + n1)²
In the very important particular case of a normal fall from air or glass onto their interface (nair " 1.0; nst = 1.5) it is " 4%.
The nature of the polarization of reflected light changes with changes in j and is different for components of incident light polarized parallel (p-component) and perpendicular (s-component) to the plane of incidence. By plane of polarization we mean, as usual, the plane of oscillations electric vector light wave. At angles j equal to the so-called Brewster angle (see Brewster's law), the reflected light becomes completely polarized perpendicular to the plane of incidence (the p-component of the incident light is completely refracted into the reflecting medium; if this medium strongly absorbs light, then the refracted p-component passes into environment is a very small path). This feature of the mirror O. s. used in a number of polarizing devices. For j larger than the Brewster angle, the reflection coefficient from dielectrics increases with increasing j, tending to 1 in the limit, regardless of the polarization of the incident light. In a specular optical system, as is clear from Fresnel's formulas, the phase of reflected light in the general case changes abruptly. If j = 0 (light falls normally to the interface), then for n2 > n1 the phase of the reflected wave shifts by p, for n2< n1 - остаётся неизменной. Сдвиг фазы при О. с. в случае j ¹ 0 может быть различен для р- и s-составляющих падающего света в зависимости от того, больше или меньше j угла Брюстера, а также от соотношения n2 и n1. О. с. от поверхности оптически менее плотной среды (n2 < n1) при sin j ³ n2 / n1 является полным внутренним отражением, при котором вся энергия падающего пучка лучей возвращается в 1-ю среду. Зеркальное О. с. от поверхностей сильно отражающих сред (например, металлов) описывается формулами, подобными формулам Френеля, с тем (правда, весьма существенным) изменением, что n2 становится комплексной величиной, мнимая часть которой характеризует поглощение падающего света.
Absorption in a reflective medium leads to the absence of a Brewster angle and higher (compared to dielectrics) values of the reflection coefficient - even at normal incidence it can exceed 90% (this explains the widespread use of smooth metal and metallized surfaces in mirrors). The polarization characteristics also differ. light waves reflected from the absorbing medium (due to other phase shifts of the p- and s-components of the incident waves). The nature of the polarization of reflected light is so sensitive to the parameters of the reflecting medium that numerous optical methods for studying metals are based on this phenomenon (see Magneto-optics, Metal-optics).
Diffuse O. s. - its dispersion by the uneven surface of the 2nd medium in all possible directions. The spatial distribution of the reflected radiation flux and its intensity are different in different specific cases and are determined by the relationship between l and the size of the irregularities, the distribution of irregularities over the surface, lighting conditions, and the properties of the reflecting medium. The limiting case of spatial distribution of diffusely reflected light, which is not strictly fulfilled in nature, is described by Lambert’s law. Diffuse O. s. also observed from environments internal structure which is inhomogeneous, which leads to the scattering of light in the volume of the medium and the return of part of it to the 1st medium. Patterns of diffuse O. s. from such media are determined by the nature of the processes of single and multiple light scattering in them. Both absorption and scattering of light can exhibit a strong dependence on l. The result of this is a change in the spectral composition of diffusely reflected light, which (when illuminated with white light) is visually perceived as the color of bodies.
Total internal reflection
As the angle of incidence increases i, the angle of refraction also increases, while the intensity of the reflected beam increases, and the refracted beam decreases (their sum is equal to the intensity of the incident beam). At some value i = i k corner r= π / 2, the intensity of the refracted beam will become equal to zero, all the light will be reflected. With further increase in angle i > i k There will be no refracted ray; the light is completely reflected.
We will find the value of the critical angle of incidence at which total reflection begins, put it in the law of refraction r= π / 2, then sin r= 1 means:
sin i k = n 2 / n 1Diffuse light scattering
θ i = θ r .
The angle of incidence is equal to the angle of reflection
Operating principle of a corner reflector
Wikimedia Foundation.
2010.
See what “Reflection of light” is in other dictionaries: The phenomenon that when light (optical radiation) falls from the first medium onto the interface with the second medium, the interaction of light with the second medium leads to the appearance of a light wave propagating from the interface back to the first... ...
Physical encyclopedia The return of a light wave when it is incident on the interface between two media with different refractive indices back into the first medium. There are specular reflections of light (the dimensions l of irregularities on the interface are less than the length of the light... ...
Big Encyclopedic Dictionary REFLECTION OF LIGHT, the return of part of the light beam incident on the interface between two media back to the first medium. A distinction is made between specular reflection of light (the dimensions L of irregularities on the interface are less than the light wavelength l) and diffuse reflection (L?... ...
Modern encyclopedia Reflection of light - REFLECTION OF LIGHT, the return of part of the light beam incident on the interface between two media “back” to the first medium. A distinction is made between specular reflection of light (the dimensions L of irregularities on the interface are less than the light wavelength l) and diffuse reflection (L...
Illustrated Encyclopedic Dictionary- The phenomenon that light incident on the interface between two media with different refractive indices is partially or completely returned to the medium from which it falls. [Collection of recommended terms. Issue 79. Physical... ... Technical Translator's Guide
The phenomenon that when light (optical radiation (See Optical radiation)) falls from one medium onto its interface with the 2nd medium, the interaction of light with matter leads to the appearance of a light wave,... ... Great Soviet Encyclopedia
The return of a light wave when it falls on the interface between two media with different refractive indices “back” to the first medium. There are specular reflections of light (the dimensions l of irregularities on the interface are less than the length of the light... ... encyclopedic Dictionary
Illustrated Encyclopedic Dictionary- šviesos atspindys statusas T sritis fizika atitikmenys: engl. light reflection vok. Reflexion des Lichtes, f rus. reflection of light, n pranc. réflexion de la lumière, f … Fizikos terminų žodynas