tailieunhanh - CRC Press - Dictionary of Material Science and High Energy Physics - D. Basu (2001) Episode 4

Tham khảo tài liệu 'crc press - dictionary of material science and high energy physics - d. basu (2001) episode 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | electromagnetic wave or plasma electromagnetic wave 1 One of three categories of plasma waves electromagnetic electrostatic and hydrodynamic magnetohydrodynamic . Wawe motions . plasma oscillations are inherent to plasmas due to the ion electron species electric magnetic forces pressure gradients and gas-like properties that can lead to shock waves. 2 Transverse waves characterized by oscillating electric and magnetic fields with two possible oscillation directions called polarizations. Their behavior can be described classically via a wave equation derived from Maxwell s equations and also quantum mechanically. For the latter picture the waves are replaced by particles the photons. The frequency V and the wavelength À of an electromagnetic wave obey the relationship c kv where c is the speed of light. Depending on the frequency and wavelength of the waves one can divide the electromagnetic spectrum into different parts. Name Frequency THz Wavelength nm FM AM radio television 10-7-10-3 3 X 1012 - 3 X 108 Microwaves 10-3- 3x108 - 106 Far-infrared 106 - 5 X 104 Mid-infrared 6 - 100 5 X 104 - 3000 Near-infrared 100 - 385 3000-780 Visible light 385 - 790 780-380 Ultraviolet light 790 - 1500 380-200 Vacuum ultraviolet light 1500 - 3000 200-10 X-rays 3000 - 3x107 10-1 Gamma rays 3x107-3x109 1-10-1 Within the visible light region the human eye sees the different spectral colors at approximately the following wavelengths Color Wavelength nm red 630 orange 610 yellow 580 green 532 blue 480 electron A fundamental particle which has a negative electronic charge a spin of 1 2 and undergoes the electroweak interaction. It along with its neutrino are the leptons in the first family of the standard model. electron affinity The decrease in energy when an electron is added to a neutral atom to form a negative ion. Second third and higher affinities are similarly defined as the additional decreases in energy upon the addition of successively more electrons. electron .