Physics 9 Fall 2009 - faculty.ucmerced.edu
... Large quantities of dust should have been left behind after the creation of the solar system. Larger dust particles, comperable in size to soot and sand grains, are common. They creat shooting stars when the collide with the earth’s atmosphere. But very small dust particles are conspicuously absent. ...
... Large quantities of dust should have been left behind after the creation of the solar system. Larger dust particles, comperable in size to soot and sand grains, are common. They creat shooting stars when the collide with the earth’s atmosphere. But very small dust particles are conspicuously absent. ...
Document
... electromagnetic radiation – waves produced by the motion of electrically charged particles, travel through empty space as well as air and other substances, can act like waves, stream of particles, called photons, that have no mass, photons with the highest energy correspond to the shortest wavelengt ...
... electromagnetic radiation – waves produced by the motion of electrically charged particles, travel through empty space as well as air and other substances, can act like waves, stream of particles, called photons, that have no mass, photons with the highest energy correspond to the shortest wavelengt ...
The Future of Nuclear Medicine
... The CT scanner is typically a large machine with a hole, or tunnel, in the center A major advantage of CT is that it is able to image bone, soft tissue and blood vessels all at the same time. ...
... The CT scanner is typically a large machine with a hole, or tunnel, in the center A major advantage of CT is that it is able to image bone, soft tissue and blood vessels all at the same time. ...
Introduction to the physics of light
... • James Clerk Maxwell proposed that if a changing magnetic field can make an electric field, then a changing electric field should make a magnetic field. • A consequence of this is that changing electric and magnetic fields should trigger each other and these changing fields should move at a speed e ...
... • James Clerk Maxwell proposed that if a changing magnetic field can make an electric field, then a changing electric field should make a magnetic field. • A consequence of this is that changing electric and magnetic fields should trigger each other and these changing fields should move at a speed e ...
The Atomic Zoo
... that the negative electrons were equally distributed within the corresponding positive charge in the atom – like currants in a pudding. However, in 1909, E. Rutherford bombarded thin gold foil with a beam of alpha particles (positively charged helium nuclei), and found that about 1 in 8000 particles ...
... that the negative electrons were equally distributed within the corresponding positive charge in the atom – like currants in a pudding. However, in 1909, E. Rutherford bombarded thin gold foil with a beam of alpha particles (positively charged helium nuclei), and found that about 1 in 8000 particles ...
Document
... if the tines oscillate at that frequency . The frequency of visible light is more than 1014 Hz. Electrons can vibrate at that frequency. Remember that this is just a model. In the ultraviolet range glass electrons resonant with UV waves and generate heat. In the IR range, molecules of glass resonate ...
... if the tines oscillate at that frequency . The frequency of visible light is more than 1014 Hz. Electrons can vibrate at that frequency. Remember that this is just a model. In the ultraviolet range glass electrons resonant with UV waves and generate heat. In the IR range, molecules of glass resonate ...
Basic Principles of Microwave Energy
... illustrated by tossing a pebble into a quiet pond. The pebble striking the still surface of the water creates a disturbance. The disturbance causes the water to move up and down in the form of ripples that radiate in everwidening circles over the surface of the pond (Fig 2-1). These ripples, or vibr ...
... illustrated by tossing a pebble into a quiet pond. The pebble striking the still surface of the water creates a disturbance. The disturbance causes the water to move up and down in the form of ripples that radiate in everwidening circles over the surface of the pond (Fig 2-1). These ripples, or vibr ...
ppt - Physics
... what momentum would they need to be produced in order to reach Earth before decaying? The distance between the center of our galaxy and the Sun is about 25,000 light years. The neutron has a mass of 940 MeV, and its lifetime is 886s. ...
... what momentum would they need to be produced in order to reach Earth before decaying? The distance between the center of our galaxy and the Sun is about 25,000 light years. The neutron has a mass of 940 MeV, and its lifetime is 886s. ...
The atmosphere is made up of oxygen and nitrogen mostly. Oxygen
... The atmosphere is made up of oxygen and nitrogen mostly. Oxygen absorbs some solar radiation, but mostly these two molecules only scatter light to make the sky blue. How do they do this? To understand how, we need to understand what is known as dipole radiation. Consider an electric field incident o ...
... The atmosphere is made up of oxygen and nitrogen mostly. Oxygen absorbs some solar radiation, but mostly these two molecules only scatter light to make the sky blue. How do they do this? To understand how, we need to understand what is known as dipole radiation. Consider an electric field incident o ...
Chapt38_VGO
... If photon frequency does matches a possible transition, photon can be absorbed If the atom is “cold” and all electrons are in the lowest possible states then only transitions from those states to higher states will lead to absorption. Generally fewer lines observed than for emission from a hot atoms ...
... If photon frequency does matches a possible transition, photon can be absorbed If the atom is “cold” and all electrons are in the lowest possible states then only transitions from those states to higher states will lead to absorption. Generally fewer lines observed than for emission from a hot atoms ...
Electromagnetic Radiation and Atomic Physics
... Since mp = 1836 me and mn = 1839 me, most of the mass of an atom is concentrated in its nucleus. An ion is an atom that has either a deficit or a surplus of electrons. The process of removing an electron from an atom is called “ionization”. The number of protons in the nucleus determines the chemica ...
... Since mp = 1836 me and mn = 1839 me, most of the mass of an atom is concentrated in its nucleus. An ion is an atom that has either a deficit or a surplus of electrons. The process of removing an electron from an atom is called “ionization”. The number of protons in the nucleus determines the chemica ...
What can we Learn from the Electromagnetic Spectrum?
... The seven parts of the EMS are listed in Table 1, along with their approximate wavelength and energy ranges (although in principle the EMS extends to infinity, here we only discuss the measurable part of A). The ratio between the largest and the smallest wavelength, or energy, at the two extremes of ...
... The seven parts of the EMS are listed in Table 1, along with their approximate wavelength and energy ranges (although in principle the EMS extends to infinity, here we only discuss the measurable part of A). The ratio between the largest and the smallest wavelength, or energy, at the two extremes of ...
Radiation
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: electro-magnetic radiation (also known as ""continuum radiation"") γ such as radio waves, visible light, and x-rays particle radiation such as α, β, and neutron radiation (discrete energy per particle) acoustic radiation such as ultrasound, sound, and seismic waves. (dependent on intervening mass for transmission)Radiation is often categorized as either ionizing or non-ionizing depending on the energy of the radiated particles. Ionizing radiation carries more than 10 eV, which is enough to ionize atoms and molecules, and break chemical bonds. This is an important distinction due to the large difference in harmfulness to living organisms. A common source of ionizing radiation is radioactive materials that emit α, β, or γ radiation, consisting of helium nuclei, electrons or positrons, and photons, respectively. Other sources include X-rays from medical radiography examinations and muons, mesons, positrons, neutrons and other particles that constitute the secondary cosmic rays that are produced after primary cosmic rays interact with Earth's atmosphere.Gamma rays, X-rays and the higher energy range of ultraviolet light constitute the ionizing part of the electromagnetic spectrum. The lower-energy, longer-wavelength part of the spectrum including visible light, infrared light, microwaves, and radio waves is non-ionizing; its main effect when interacting with tissue is heating. This type of radiation only damages cells if the intensity is high enough to cause excessive heating. Ultraviolet radiation has some features of both ionizing and non-ionizing radiation. While the part of the ultraviolet spectrum that penetrates the Earth's atmosphere is non-ionizing, this radiation does far more damage to many molecules in biological systems than can be accounted for by heating effects, sunburn being a well-known example. These properties derive from ultraviolet's power to alter chemical bonds, even without having quite enough energy to ionize atoms.The word radiation arises from the phenomenon of waves radiating (i.e., traveling outward in all directions) from a source. This aspect leads to a system of measurements and physical units that are applicable to all types of radiation. Because such radiation expands as it passes through space, and as its energy is conserved (in vacuum), the intensity of all types of radiation from a point source follows an inverse-square law in relation to the distance from its source. This law does not apply close to an extended source of radiation or for focused beams.