Examples of Ray Rist in the following topics:
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- Ray Rist, a sociologist, found that social class contributed to the perceptions of teachers and was a predictor of scholastic success.
- Ray Ristwas a sociologist who, in 1970, published a report linking the socioeconomic status of children to their educational achievement.
- In his 1970 article, "Student Social Class and Teachers' Expectations: The Self-Fulfilling Prophecy of Ghetto Education," Ray Rist observed an African American classroom with an African American teacher.
- Following the initial year, Rist continued to observe this group of students as they advanced in school.
- Rist's research showed that teachers judge their students' abilities after only eight days in the classroom.
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- In a previous Atom on X-rays, we have seen that there are two processes by which x-rays are produced in the anode of an x-ray tube.
- In one process, the deceleration of electrons produces x-rays, and these x-rays are called Bremsstrahlung, or braking radiation.
- The x-ray spectrum in is typical of what is produced by an x-ray tube, showing a broad curve of Bremsstrahlung radiation with characteristic x-ray peaks on it.
- Thus, typical x-ray photons act like rays when they encounter macroscopic objects, like teeth, and produce sharp shadows.
- The process is called x-ray diffraction because it involves the diffraction and interference of x-rays to produce patterns that can be analyzed for information about the structures that scattered the x-rays.
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- Gamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency and therefore high energy.
- Gamma rays have characteristics identical to X-rays of the same frequency—they differ only in source.
- The distinction between X-rays and gamma rays has changed in recent decades.
- Thus, gamma rays are now usually distinguished by their origin: X-rays are emitted by definition by electrons outside the nucleus, while gamma rays are emitted by the nucleus.
- Identify wavelength range characteristic for gamma rays, noting their biological effects and distinguishing them from gamma rays
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- Ray tracing is the technique of determining the paths light rays take; often thin lenses (the light ray bending only once) are assumed.
- Ray tracing is the technique of determining or following (tracing) the paths that light rays take.
- (See rays 1 and 3 in . )
- (See ray 2 in and . )
- The dashed lines are not rays—they indicate the directions from which the rays appear to come.
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- X-radiation (composed of x-rays) is a form of electromagnetic radiation.
- X-rays can be generated by an x-ray tube, a vacuum tube that uses high voltage to accelerate the electrons released by a hot cathode to a high velocity.
- These x-rays have a continuous spectrum.
- The intensity of the x-rays increases linearly with decreasing frequency, from zero at the energy of the incident electrons, the voltage on the x-ray tube.
- Its unique features are x-ray outputs many orders of magnitude greater than those of x-ray tubes, wide x-ray spectra, excellent collimation, and linear polarization.
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- They are shorter in wavelength than UV rays and longer than gamma rays.
- X-rays with photon energies above 5 to 10 keV (below 0.2-0.1 nm wavelength), are called hard X-rays, while those with lower energy are called soft X-rays.
- By contrast, soft X-rays are easily absorbed in air and the attenuation length of 600 eV (~2 nm) X-rays in water is less than 1 micrometer.
- The distinction between X-rays and gamma rays is somewhat arbitrary.
- Like all electromagnetic radiation, the properties of X-rays (or gamma rays) depend only on their wavelength and polarization.
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- X-ray crystallography is a method of determining the arrangement of atoms within molecules.
- X-ray crystallography is a method for determining the arrangement of atoms within a crystal structure.
- The crystal is typically rotated with respect to different axes and shot again with X-rays, so that diffraction patterns from all angles of the X-rays hitting the crystal are recorded.
- When bombarded with x-ray radiation, crystals exhibit a characteristic diffraction pattern.
- An X-ray diffraction pattern of a crystallized protein molecule.
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- Radiography uses x-rays to view material that cannot be seen by the human eye by identifying areas of different density and composition.
- X-ray imaging, or radiography, used x-rays to view material within the body that cannot be seen by the human eye by identifying areas of different density and composition.
- X-ray radiographs are produced by projecting a beam of X-rays toward an object, in medical cases, a part of the human body.
- Depending on the physical properties of the object (density and composition), some of the X-rays can be partially absorbed.
- The portion of the rays that are not absorbed then pass through the object and are recorded by either film or a detector, like in a camera.
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- The movement of light, as a ray, can be shown with simple geometry and trigonometry.
- The light will continue in a straight line or ray until it reaches the observer.
- This causes the light rays to change direction .
- This is when a light ray, the incident ray, hits a reflective material and bounces off as the reflected ray at a specific angle.
- This diagram shows how light rays reflects off of a surface.
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- Recall the five basic rules of ray tracing:
- The figure shows three rays from the top of the object that can be traced using the five ray tracing rules.
- It is best to trace rays for which there are simple ray tracing rules.
- Rays originating from the same point on the object are traced—the three chosen rays each follow one of the rules for ray tracing, so that their paths are easy to determine.
- The image is located at the point where the rays cross.