Why Is the Angle of Incidence Equal to the Angle of Reflection? An Activity

2021 ◽  
Vol 59 (8) ◽  
pp. 650-651
Author(s):  
Shirish R. Pathare ◽  
Bhagyashri G. Latad ◽  
Rohan D. Lahane ◽  
Saurabhee S. Huli
Keyword(s):  
Angle Of Incidence ◽  
Angle Of Reflection

Wechselwirkung kondensierter Molekularstrahlen mit festen Oberflächen

1968 ◽  
Vol 23 (2) ◽  
pp. 274-279 ◽  
Author(s):  
E. W. Becker ◽  
R. Klingelhöfer ◽  
H. Mayer
Keyword(s):  
Steel Surface ◽  
Tangential Velocity ◽  
Incident Beam ◽  
Stainless Steel Surface ◽  
Angle Of Incidence ◽  
Mean Velocity ◽  
Tangential Velocity Component ◽  
Polished Stainless Steel ◽  
The Mean ◽  
Angle Of Reflection

The reflection of a beam of nitrogen clusters from a polished stainless steel surface is investigated. The scattered flux shows a strong maximum at an angle of reflection almost 90°, independent of angle of incidence. The mean velocity of the reflected beam is about equal to the tangential velocity component of the incident beam. Measurements with increased background pressure demonstrate that the reflected beam still consists essentially of clusters.

II. Geometrical optics of variable-frequency light rays in special relativistic and nonrelativistic situations:The general law of reflection

2000 ◽  
Vol 78 (8) ◽  
pp. 747-754 ◽  
Author(s):  
W T Chyla
Keyword(s):  
Coherent Scattering ◽  
Skin Depth ◽  
Variable Frequency ◽  
Angle Of Incidence ◽  
X Rays ◽  
Reflection Point ◽  
General Law ◽  
Light Rays ◽  
Relativistic Treatment ◽  
Angle Of Reflection

The general law of reflection concerns situations when the light ray undergoes a shift of frequency at the reflection point. For example, it governs reflection of light rays from a moving mirror (either in a vacuum or in a transparent medium), reflection from a motionless mirror coated with a layer of Raman-active molecules in the coherent-scattering regime, or external reflection of X-rays from the surface of a condensed matter sample, with partial dissipation of energy within the skin depth. The general law of reflection is derived from the extremum principle for propagation of variable-frequency light rays. It states that the angle of reflection depends not only on the angle of incidence but also on the frequency shift in the reflection point and dispersion of the refractive index of the medium in contact with the mirror. The compatibility of the general law of reflection and the special relativistic treatment of reflection is examined in detail. Applications of the new law of reflection are discussed in the special relativistic and the nonrelativistic regime. PACS Nos.: 42.15-i, 03.30+p

Gloss Evaluation of Hairline-Finished Metal Surface Using Patterned Area Illumination Method: Reproduction of Gloss Evaluation by Ray Tracing

2015 ◽  
Vol 656-657 ◽  
pp. 468-472 ◽  
Author(s):  
Tadanori Sugino ◽  
Yasuo Yamane
Keyword(s):  
Surface Roughness ◽  
Ray Tracing ◽  
Metal Surface ◽  
Surface Finish ◽  
Quality Evaluation ◽  
Specular Reflection ◽  
Angle Of Incidence ◽  
Striped Pattern ◽  
Illumination Method ◽  
Angle Of Reflection

Gloss of a metal surface is an important aspect for product quality evaluation. Evaluating the specular reflection is almost the same as evaluating the gloss. We propose a method that uses patterned area illumination to evaluate specular reflection. In specular reflection, the angle of incidence equals the angle of reflection. Consequently, when light (ray) of the area illumination, which has a striped pattern, are projected on a glossy metal surface, a striped pattern forms on the reflected image as a mirror-like reflection, and the sharpness of the striped pattern of the image provides information about the specular reflection on the surface. This characteristic is applied to a metal with a hairline surface finish. A hairline surface presents different glossiness at different viewpoints. When the direction of the striped pattern of illumination is changed, the sharpness of striped pattern on the reflected image varies owing to the surface roughness of the hairline finish. Therefore, we can evaluate the glossiness in various directions by rotating the pattern. The relationships between gloss evaluation value and surface roughness were indicated in our study. We tried the reproduction of the gloss evaluation by ray tracing to obtain the more detailed relationships between them. Ray tracing is a technique to generate an image in computer graphics. The approximate reproduction of gloss evaluation was obtained by the simulation.

The significance of ricochet marks in finding bullets at the shooting scene and in determining shooter location

2015 ◽  
Vol 287 ◽  
pp. 101-106
Author(s):  
Julia Mazur ◽  
◽  
Paweł Faliszewski ◽  
Keyword(s):  
Angle Of Incidence ◽  
Powder Charge ◽  
Impact Site ◽  
Muzzle Velocity ◽  
Steel Core ◽  
Different Types ◽  
Location Finding ◽  
Trajectory Pattern ◽  
Experimental Firing ◽  
Angle Of Reflection

The article offers an overview of the ricochet phenomenon. The authors addresses the issue of examining bullet trajectories that have been deflected as a result of coming into contact with different types of obstacles. Ricochet marks are used by forensic experts to determine bullet trajectory, pattern, caliber and shooter location. Finding the ricocheted projectiles is difficult due to the fact that the angles of incidence (impact) and reflection are not equal. This article, devoted to ballistics and ricochet phenomenon, is based on the findings of the study conducted by specialists of the MWD Academy, Volgograd, Russia. The above study involved the use of a small semiautomatic 5.45 mm PSM pistol. Experimental firing was conducted with 5.45 mm pistol cartridges with central ignition (MPC); 2.5 g steel-core bullet; 0.15-0.17 g powder charge (Sf 040 gunpowder); muzzle velocity: 315–325 m/s. The shooting targets involved 16 mm particleboards (DSP) covered with laminate and without laminate, removed from old furniture. The results of 17 experimental firings are shown in this article. For all the firing trials, the muzzle was positioned at a distance of 2 m from the anticipated impact site. Based on the obtained results, it can be inferred that for all the ricochet incidents, the angle of reflection was greater than the angle of incidence. The projectile penetrated the particleboard over a certain distance and exited out the front site. The analysis of findings will in the future serve the formulation of the conclusions about the shooting scene, including finding the projectiles. The authors developed the following sequence of recommended expert activities: determining the type of projectile, trajectory, angles of incidence and reflection, shooter position and finally, the search for a projectile.

Evaluation of Biangular Reflection Photometry for Quantitative Study of Etched Alloy Surface Roughness

1987 ◽  
Vol 66 (8) ◽  
pp. 1350-1355 ◽  
Author(s):  
J.R. Kelly ◽  
W.A. Brantle
Keyword(s):  
Surface Roughness ◽  
Quantitative Study ◽  
Specular Reflection ◽  
Angle Of Incidence ◽  
Viewing Angle ◽  
Nickel Chromium ◽  
Reflection Peak ◽  
Quantitative Stereology ◽  
Pit Depth ◽  
Angle Of Reflection

Biangular reflection photometry was correlated with quantitative stereology and direct pit-depth measurements for an electrolytically etched nickel-chromium-beryllium alloy. Effects of viewing angle, viewing aperture, and plane polarization of incident and viewing light were also studied. The results showed that architectural changes in the etched metal surface could be quantitatively described with the use of reflection photometry. An off-specular peak, located at an angle of reflection considerably different from the angle of incidence, was observed to have an intensity comparable with that of the specular reflection peak. Viewing aperture was found to affect one's ability to distinguish among degrees of surface roughness.

Gloss Evaluation of Hairline-Finished Metal Surface Using Patterned Area Illumination Method: Relationship between Gloss Evaluation and Surface Roughness for the Estimation of Surface Roughness

2017 ◽  
Vol 749 ◽  
pp. 251-256 ◽  
Author(s):  
Tadanori Sugino ◽  
Yuki Tashiro ◽  
Yasuo Yamane
Keyword(s):  
Surface Roughness ◽  
Metal Surface ◽  
Quality Evaluation ◽  
Specular Reflection ◽  
Angle Of Incidence ◽  
Striped Pattern ◽  
Illumination Method ◽  
Precise Relationship ◽  
Angle Of Reflection ◽  
The Relationship

The gloss of a metal surface is an important aspect for product quality evaluation. In general, gloss is influenced by specular reflection of light on a metal surface. Therefore, evaluating the specular reflection is almost the same as evaluating the gloss. We propose a method that uses patterned area illumination to evaluate specular reflection. In specular reflection, the angle of incidence equals the angle of reflection. Consequently, when light (ray) of the area illumination, which has a striped pattern, are projected on a glossy metal surface, a striped pattern forms on the reflected image as a mirror-like reflection, and the sharpness of the striped pattern of the image provides information about the specular reflection on the surface. This characteristic is applied to a metal with a hairline surface finish. A hairline surface presents different glossiness at different viewpoints. When the direction of the striped pattern of illumination is changed, the sharpness of striped pattern on the reflected image varies owing to the surface roughness of the hairline finish. Therefore, we can evaluate the glossiness in various directions by rotating the pattern. The rough relationships between gloss evaluation value and surface roughness were indicated in our study. In order to make the relationship between gloss evaluation and surface roughness for the estimation of surface roughness, we had tried the comparison for the gloss evaluation value and the surface roughness. The more precise relationship for seven directions on hairline-finished metal surface was measured. This report describes the results and considers the possibility of estimation of surface roughness by the gloss evaluation value.

Gloss Evaluation Method for Metal Surface with Hairline Using Patterned Area Illumination

2009 ◽  
Vol 407-408 ◽  
pp. 723-726 ◽  
Author(s):  
Tadanori Sugino ◽  
Yumi Satozono ◽  
Yasuo Yamane
Keyword(s):  
Surface Roughness ◽  
Metal Surface ◽  
Evaluation Method ◽  
Specular Reflection ◽  
Point Of View ◽  
Angle Of Incidence ◽  
Stripe Pattern ◽  
Reflection Image ◽  
Reflection Of Light ◽  
Angle Of Reflection

Gloss evaluation of a metal surface is important for the quality as the product. In general, gloss of a metal surface is influenced by specular reflection of light on the surface. Therefore to evaluate the specular reflection is almost the same as the evaluation of the gloss. We propose the method to evaluate the specular reflection using patterned area illumination. In the specular reflection, the angle of incidence is equal to the angle of reflection. Consequently when lights (rays) of the area illumination which has a stripe pattern are projected to a glossy metal surface, the stripe pattern occurs on the reflection image by the mirror-like reflection and the sharpness of the stripe pattern of the image has information of the specular reflection on the surface. This character is applied for the metal surface with hairline. The metal surface with hairline has different gloss feeling at different point of view. When the direction of the stripe pattern of the illumination is changed, the sharpness of stripe pattern on the reflection image varies owing to the surface roughness of hairline. Therefore we can evaluate the glossiness for various directions by rotating the stripe pattern. This paper shows the availability of the proposed method through the experiment.

Process Highlighters in a Computer Simulation: Facilitation of Theory-Oriented Problem Solving

1993 ◽  
Vol 9 (2) ◽  
pp. 237-263 ◽  
Author(s):  
Terrell N. Chandler ◽  
Christine Chaillé
Keyword(s):  
Computer Simulation ◽  
Problem Solving ◽  
Computer Game ◽  
Early Adolescent ◽  
Angle Of Incidence ◽  
Perceptual Cues ◽  
Problem Domain ◽  
Level Of Understanding ◽  
Angle Of Reflection ◽  
The Relationship

This experiment investigates whether or not process highlighters, incorporated in a computer simulation, facilitate the knowledge representation of early adolescent children. Process highlighters are perceptual cues (usually visual) that are designed to focus attention toward critical features of events and processes occurring in a problem domain. The two questions addressed in this study are: a) do process highlighters increase the percentage of subjects who employ theory-oriented explanation?, and b) do process highlighters increase the percentage of subjects who demonstrate an understanding of the concept presented in the simulation? Thirty-two twelve-year-old children from two middle schools played a computer game about light reflecting off flat mirrors, presenting the physical law that the angle of incidence equals the angle of reflection. Each child played either the game with process highlighters or the game without process highlighters for forty minutes. Three independent evaluators analyzed each subject's transcript to determine his/her mode of explanation (random, concrete, or hypothetical) and also the level of understanding (none, preliminary, or good). The results indicate that the use of process highlighters is positively correlated with the subject's level of understanding, but is less conclusive with respect to encouraging students to use theory-oriented problem solving. The results are interpreted with respect to clarifying the relationship between a student's understanding of a concept and his or her expressing that understanding in concrete or hypothetical terms.

Electron Channeling Patterns

1977 ◽  
Vol 35 ◽  
pp. 12-13
Author(s):  
David C. Joy
Keyword(s):  
Electron Diffraction ◽  
Incidence Angle ◽  
Photographic Plate ◽  
Diffraction Effect ◽  
Angle Of Incidence ◽  
Bulk Single Crystal ◽  
Time Resolved ◽  
Electron Channeling ◽  
Spatially Resolved ◽  
Large Bulk

Electron channeling patterns (ECP) were first found by Coates (1967) while observing a large bulk, single crystal of silicon in a scanning electron microscope. The geometric pattern visible was shown to be produced as a result of the changes in the angle of incidence, between the beam and the specimen surface normal, which occur when the sample is examined at low magnification (Booker, Shaw, Whelan and Hirsch 1967).A conventional electron diffraction pattern consists of an angularly resolved intensity distribution in space which may be directly viewed on a fluorescent screen or recorded on a photographic plate. An ECP, on the other hand, is produced as the result of changes in the signal collected by a suitable electron detector as the incidence angle is varied. If an integrating detector is used, or if the beam traverses the surface at a fixed angle, then no channeling contrast will be observed. The ECP is thus a time resolved electron diffraction effect. It can therefore be related to spatially resolved diffraction phenomena by an application of the concepts of reciprocity (Cowley 1969).

Electron-Channelling Patterns: Principles and Techniques

1976 ◽  
Vol 34 ◽  
pp. 400-401
Author(s):  
David C. Joy
Keyword(s):  
Crystal Structure ◽  
Electron Flux ◽  
Lattice Structure ◽  
Incident Beam ◽  
Bloch Wave ◽  
Crystalline Solid ◽  
Angle Of Incidence ◽  
Electron Channelling ◽  
Regular Arrangement ◽  
Backscattered Signals

In a crystalline solid the regular arrangement of the lattice structure influences the interaction of the incident beam with the specimen, leading to changes in both the transmitted and backscattered signals when the angle of incidence of the beam to the specimen is changed. For the simplest case the electron flux inside the specimen can be visualized as the sum of two, standing wave distributions of electrons (Fig. 1). Bloch wave 1 is concentrated mainly between the atom rows and so only interacts weakly with them. It is therefore transmitted well and backscattered weakly. Bloch wave 2 is concentrated on the line of atom centers and is therefore transmitted poorly and backscattered strongly. The ratio of the excitation of wave 1 to wave 2 varies with the angle between the incident beam and the crystal structure.

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