Relativistic effects in the dynamical Casimir effect
... ǫ0 cos (ω0t) e−|t|/τ , where ǫ0 is the amplitude, ω0 is the characteristic frequency and τ is the effective time interval of the oscillation, we have found analytical formulas for the particle creation spectrum: dN(ω) /dω = ǫ2N2(ω) + ǫ4N4(ω) , where N2(ω) immediately recover the non-relativistic par ...
... ǫ0 cos (ω0t) e−|t|/τ , where ǫ0 is the amplitude, ω0 is the characteristic frequency and τ is the effective time interval of the oscillation, we have found analytical formulas for the particle creation spectrum: dN(ω) /dω = ǫ2N2(ω) + ǫ4N4(ω) , where N2(ω) immediately recover the non-relativistic par ...
View File
... Appendix: Superconductivity 1911: H. K. Onnes, who had figured out how to make liquid helium, used it to cool mercury to 4.2 K and looked at its resistance: ...
... Appendix: Superconductivity 1911: H. K. Onnes, who had figured out how to make liquid helium, used it to cool mercury to 4.2 K and looked at its resistance: ...
Electricity and Magnetism
... 12. These circuits allow the continuous flow of electrical energy. a. open circuits b. conductor circuits c. thermal circuits d. closed circuits ...
... 12. These circuits allow the continuous flow of electrical energy. a. open circuits b. conductor circuits c. thermal circuits d. closed circuits ...
Physics 121 Practice Problem Solutions 07 Current and Resistance
... a wire over four different time periods. Rank the periods according to the net charge that passes through the cross section during each, greatest first. ...
... a wire over four different time periods. Rank the periods according to the net charge that passes through the cross section during each, greatest first. ...
Name ______ period ____
... What type of current is produced by the plug in the wall? ______alternating current or AC______ 24. There is a potential difference of 15 V across a resistor with 1.4 A of current in it. What is the resistance of the resistor? V = I x R or R = V / I so 15V / 1.4 A = 10.71Ω 25. An electrical conducto ...
... What type of current is produced by the plug in the wall? ______alternating current or AC______ 24. There is a potential difference of 15 V across a resistor with 1.4 A of current in it. What is the resistance of the resistor? V = I x R or R = V / I so 15V / 1.4 A = 10.71Ω 25. An electrical conducto ...
Essay 90-4cd DC motor
... bulb using the methods in (I) [ smoothing is not required ]. Show that the current generated is always flowing in one direction through the bulb. ii) Explain carefully why a greater driving torque is needed to maintain the coil of the generator rotating at the original speed when an identical light ...
... bulb using the methods in (I) [ smoothing is not required ]. Show that the current generated is always flowing in one direction through the bulb. ii) Explain carefully why a greater driving torque is needed to maintain the coil of the generator rotating at the original speed when an identical light ...
Unit 1
... The EMF induced in the second coil, called the secondary voltage, is proportional to the primary voltage. The secondary voltage also depends on the ratio of turns on the secondary coil to turns on the primary coil. ...
... The EMF induced in the second coil, called the secondary voltage, is proportional to the primary voltage. The secondary voltage also depends on the ratio of turns on the secondary coil to turns on the primary coil. ...
solutions
... H. The elements are in series with an open switch. What is the voltage across the inductor 2.0 s after the switch is closed? Answer: 2.6 V Solution: The emf across the inductor in an LR circuit is given by !VL = Ee "t/# , where ! = L / R = 1.6 s. Solving yields an emf of 2.6 V. 8. A proton cyclotron ...
... H. The elements are in series with an open switch. What is the voltage across the inductor 2.0 s after the switch is closed? Answer: 2.6 V Solution: The emf across the inductor in an LR circuit is given by !VL = Ee "t/# , where ! = L / R = 1.6 s. Solving yields an emf of 2.6 V. 8. A proton cyclotron ...
vortices - University of Toronto Physics
... The vortices themselves are quantum excitations- so they also have a probability density! They have fascinating properties, many of which were first discussed by Feynman in the early 1950’s, as fully quantum-mechanical objects. We now know that most of the flow properties of He superfluid are govern ...
... The vortices themselves are quantum excitations- so they also have a probability density! They have fascinating properties, many of which were first discussed by Feynman in the early 1950’s, as fully quantum-mechanical objects. We now know that most of the flow properties of He superfluid are govern ...
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.