Quanta: a new view of the world
... The atom was the first to go. It had been known for some time that when a high voltage is applied to two separated pieces of metal in an evacuated tube, "cathode rays" pass between them. These rays could be detected by their ability to cause certain materials to give off light, or fluoresce, and wer ...
... The atom was the first to go. It had been known for some time that when a high voltage is applied to two separated pieces of metal in an evacuated tube, "cathode rays" pass between them. These rays could be detected by their ability to cause certain materials to give off light, or fluoresce, and wer ...
Ch 33 Electromagnetic Waves I
... 性) nuclei [such as 60Co (鈷) and 137Cs (銫)] and during certain nuclear reactions. High-energy gamma rays are a component of cosmic rays (宇宙射線) that enter the Earth’s atmosphere from space. They have wavelengths ranging from 10-10m~10-14m. They are highly penetrating and produce serious damage when ab ...
... 性) nuclei [such as 60Co (鈷) and 137Cs (銫)] and during certain nuclear reactions. High-energy gamma rays are a component of cosmic rays (宇宙射線) that enter the Earth’s atmosphere from space. They have wavelengths ranging from 10-10m~10-14m. They are highly penetrating and produce serious damage when ab ...
Atmospheric Radiation Basics
... EM waves always travel in a vacuum at an absolutely constant speed: the speed of light c=3x10^8 m/s EM waves require no material medium in which to propagate (pond ripples need a pond to propagate, sound needs air to propagate). Interacting with matters (such as the atmosphere and its various reside ...
... EM waves always travel in a vacuum at an absolutely constant speed: the speed of light c=3x10^8 m/s EM waves require no material medium in which to propagate (pond ripples need a pond to propagate, sound needs air to propagate). Interacting with matters (such as the atmosphere and its various reside ...
Physics of Radiation Oncology: Production of X Rays / Clinical
... Other Megavoltage Units • The Van de Graaff Generator – is an electrostatic accelerator; the unit accelerates electrons to approximately 2 MV. – electrons are “sprayed” onto a moving belt where they are transported to a metallic dome and allowed to accumulate. – The accumulation of charge creates a ...
... Other Megavoltage Units • The Van de Graaff Generator – is an electrostatic accelerator; the unit accelerates electrons to approximately 2 MV. – electrons are “sprayed” onto a moving belt where they are transported to a metallic dome and allowed to accumulate. – The accumulation of charge creates a ...
physics_question bank
... Wave, Microwave, Infrared Rays and Visible light, give the important properties and uses of each part. Radio waves – These are the e. m. waves of longest wavelength and minimum frequency. Wavelength range - 600m to 0.1 m Frequency range 500 KHz to 100 MHz. Source Accelerated motion of charges in con ...
... Wave, Microwave, Infrared Rays and Visible light, give the important properties and uses of each part. Radio waves – These are the e. m. waves of longest wavelength and minimum frequency. Wavelength range - 600m to 0.1 m Frequency range 500 KHz to 100 MHz. Source Accelerated motion of charges in con ...
phy workshop sep 16_ EM_WAVES
... (ii) To photograph internal parts of a human body (iii)For taking photographs during nights and foggy conditions (iv) In water purification (i) Microwaves, (ii) X rays, (iii)Infrared rays and (iv)UV rays Find the wavelength of electromagnetic wave of frequency 4X109Hz in free space. Give its two app ...
... (ii) To photograph internal parts of a human body (iii)For taking photographs during nights and foggy conditions (iv) In water purification (i) Microwaves, (ii) X rays, (iii)Infrared rays and (iv)UV rays Find the wavelength of electromagnetic wave of frequency 4X109Hz in free space. Give its two app ...
EM Radiation Basics - Millersville Meteorology
... Electromagnetic (EM) radiation is defined as “energy propagated in the form of an advancing electric and magnetic field disturbance.” (Glossary of Meteorology, edited by T. Glickman, AMS, 2000) The electric and magnetic field vectors are at 90°° to one-another. EM radiation propagates through ...
... Electromagnetic (EM) radiation is defined as “energy propagated in the form of an advancing electric and magnetic field disturbance.” (Glossary of Meteorology, edited by T. Glickman, AMS, 2000) The electric and magnetic field vectors are at 90°° to one-another. EM radiation propagates through ...
HW9 - MIT
... where I is the intensity of one of the trapping laser beams, n is the number density of atoms in the cloud, σL is the cross-section for absorption of the laser beam, and σR is the cross-section for absorption of the scattered light. (Hint: Find the magnitude of the force between two atoms separated ...
... where I is the intensity of one of the trapping laser beams, n is the number density of atoms in the cloud, σL is the cross-section for absorption of the laser beam, and σR is the cross-section for absorption of the scattered light. (Hint: Find the magnitude of the force between two atoms separated ...
Section 34 - University of Colorado Colorado Springs
... If a microwave oven intended for use with a turntable is instead used with a cooking dish in a fixed position, the antinodes can appear as burn marks on foods such as carrot strips or cheese. The separation distance between the burns is measured to be 6 cm ± 5%. From these data, calculate the speed ...
... If a microwave oven intended for use with a turntable is instead used with a cooking dish in a fixed position, the antinodes can appear as burn marks on foods such as carrot strips or cheese. The separation distance between the burns is measured to be 6 cm ± 5%. From these data, calculate the speed ...
Discrete emission spectra
... current I flows upwards and then downwards). The current creates a magnetic field ( B points in and out of the surface of the paper), which induces an electric field perpendicular to it. This changing field propagates in space. ...
... current I flows upwards and then downwards). The current creates a magnetic field ( B points in and out of the surface of the paper), which induces an electric field perpendicular to it. This changing field propagates in space. ...
velocity components and the magnetic fields are in the transverse
... Newton force equation that is responsible for the ponderomotive force. As the undulator field varies as eikuz and the radiation field as ei(kz-wt), we find that the v´B term varies as ei((ku+k)z-wt). Hence it has a phase velocity that is less than the speed of light in vacuum. Therefore an electron ...
... Newton force equation that is responsible for the ponderomotive force. As the undulator field varies as eikuz and the radiation field as ei(kz-wt), we find that the v´B term varies as ei((ku+k)z-wt). Hence it has a phase velocity that is less than the speed of light in vacuum. Therefore an electron ...
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.