California State Standards c. Students know any resistive element in
... California State Standards c. Students know any resistive element in a DC circuit dissipates energy, which heats the resistor. Students can calculate the power (rate of energy dissipation) in any resistive circuit element by using the formula Power = IR (potential difference) ×I (current) = I2R. d. ...
... California State Standards c. Students know any resistive element in a DC circuit dissipates energy, which heats the resistor. Students can calculate the power (rate of energy dissipation) in any resistive circuit element by using the formula Power = IR (potential difference) ×I (current) = I2R. d. ...
Lecture 15. Magnetic Fields of Moving Charges and Currents
... magnetic field that the point charge produces at point P A. points from the charge toward point P. B. points from point P toward the charge. C. is perpendicular to the line from the point charge to point P. D. is zero. E. The answer depends on the speed of the point charge. ...
... magnetic field that the point charge produces at point P A. points from the charge toward point P. B. points from point P toward the charge. C. is perpendicular to the line from the point charge to point P. D. is zero. E. The answer depends on the speed of the point charge. ...
The Biot-Savart law
... your fingers, the circulation is positive, and the current that flows in the direction of your thumb is a positive current. Stated one more way: if you walk counter-clockwise around an Amperian loop that lies in the plane of the page, a positive enclosed current points out of the page and will produ ...
... your fingers, the circulation is positive, and the current that flows in the direction of your thumb is a positive current. Stated one more way: if you walk counter-clockwise around an Amperian loop that lies in the plane of the page, a positive enclosed current points out of the page and will produ ...
Slides
... contracting wormhole solution and that the weak energy condition be satisfied. It was also found that in the presence of an electric field, a problematic issue was verified, namely, that the latter become singular at the throat. However, regular solutions of traversable wormholes in the presence of ...
... contracting wormhole solution and that the weak energy condition be satisfied. It was also found that in the presence of an electric field, a problematic issue was verified, namely, that the latter become singular at the throat. However, regular solutions of traversable wormholes in the presence of ...
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.