Parallel electric fields accelerating ions and electrons
... Klumpar and Heikkila (1982) reported observations from the ISIS-2 spacecraft at quite low altitudes of narrow upward moving electron beams with very soft energy spectra. The peak flux was below 100 eV and sometimes even below 10 eV. In a few cases they saw also perpendicularly accelerated ions, whic ...
... Klumpar and Heikkila (1982) reported observations from the ISIS-2 spacecraft at quite low altitudes of narrow upward moving electron beams with very soft energy spectra. The peak flux was below 100 eV and sometimes even below 10 eV. In a few cases they saw also perpendicularly accelerated ions, whic ...
Ohm’s Law
... How much current will flow through a lamp that has a resistance of 60 Ω when 12V are impressed across it? voltage Current = resistance ...
... How much current will flow through a lamp that has a resistance of 60 Ω when 12V are impressed across it? voltage Current = resistance ...
Physics 2102 Spring 2002 Lecture 15
... The circuit shown in the figure consists of a wire loop connected to a sensitive ammeter (known as a "galvanometer"). If we approach the loop with a permanent magnet we see a current being registered by the galvanometer. 1. A current appears only if there is relative motion between the magnet and th ...
... The circuit shown in the figure consists of a wire loop connected to a sensitive ammeter (known as a "galvanometer"). If we approach the loop with a permanent magnet we see a current being registered by the galvanometer. 1. A current appears only if there is relative motion between the magnet and th ...
Astronomy Astrophysics Pulsar timing irregularities and the imprint of magnetic field evolution
... Page et al. 2000, for a qualitative discussion). Since the conductivity increases with decreasing temperature, Ohmic diffusion becomes an increasingly slow process in older pulsars, beyond the transition from neutrino dominated to photon cooling at 105 yr. The only general fact that we can expect is ...
... Page et al. 2000, for a qualitative discussion). Since the conductivity increases with decreasing temperature, Ohmic diffusion becomes an increasingly slow process in older pulsars, beyond the transition from neutrino dominated to photon cooling at 105 yr. The only general fact that we can expect is ...
Electric Current (I) The rate of flow of charge through any cross
... valve, triode valve, transistor , vacuum tubes etc. For non-ohmic conductors V – I graph is not a straight line. ...
... valve, triode valve, transistor , vacuum tubes etc. For non-ohmic conductors V – I graph is not a straight line. ...
Magnetic Fields
... When a current carrying conductor is placed in a magnetic field, a potential difference is generated in a direction perpendicular to both the current and the magnetic field This phenomena is known as the Hall effect It arises from the deflection of charge carriers to one side of the conductor as a r ...
... When a current carrying conductor is placed in a magnetic field, a potential difference is generated in a direction perpendicular to both the current and the magnetic field This phenomena is known as the Hall effect It arises from the deflection of charge carriers to one side of the conductor as a r ...
Superconductivity
Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. It was discovered by Dutch physicist Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of perfect conductivity in classical physics.The electrical resistivity of a metallic conductor decreases gradually as temperature is lowered. In ordinary conductors, such as copper or silver, this decrease is limited by impurities and other defects. Even near absolute zero, a real sample of a normal conductor shows some resistance. In a superconductor, the resistance drops abruptly to zero when the material is cooled below its critical temperature. An electric current flowing through a loop of superconducting wire can persist indefinitely with no power source.In 1986, it was discovered that some cuprate-perovskite ceramic materials have a critical temperature above 90 K (−183 °C). Such a high transition temperature is theoretically impossible for a conventional superconductor, leading the materials to be termed high-temperature superconductors. Liquid nitrogen boils at 77 K, and superconduction at higher temperatures than this facilitates many experiments and applications that are less practical at lower temperatures.