# Tag Info

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I think you are really asking two questions. Can positrons serve as charge carriers in electric circuits? Theoretically, yes, if you replaced every matter particle in an electric circuit with a corresponding anti-matter particle, the circuit would work the same way (except the flow of electric charge would be in the opposite direction). However in practice ...

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A permanent magnet has an associated magnetic field (obviously). What is not as obvious is that the magnetic field has an energy density which is proportional to $B^2$. When two magnets are aligned such that their magnetic fields are in the opposite direction then the energy in the field is reduced. This leads to a force (opposites attract) which can do work....

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Among other things it violates conservation of energy. Generating a current requires you to push the electrons in the part of the wire that's near to you into their neighboring electrons, which then must push into their neighbors, all the way down the line. Obviously the electrons at each stage resist this due to repelling charges, so you need to do work ...

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This is to supplement Andrew's answer and focuses on other sub-questions. Electricity, more precisely electric current, is the flow of electric charges. Electrons are very convenient charge carriers as they move relatively easily (though not without collisions) through a lattice-like grid of nuclei in a metal (have a look at the sea of electrons model for ...

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You can for a short time, but not permanently. Energy is conserved. It can change from one form to another, but you can't create it or destroy it. Potential energy is is one form of energy. Kinetic energy is another. An electric current is moving electrons. It also contains a form of energy. Suppose you have two magnets separate by a short distance. One is ...

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The calculations seem right. Yes, it is surprising how much energy it takes to heat water, or how much energy sunlight can produce. When heat is involved the energy is high (sunlight can feel very hot sometimes). So, for example, if you wanted to reduce your household energy bill, turning off a radio would make almost no difference, but turning off an ...

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I Think this is a good question, because you have arrived at the right answer but do not feel confidence in your methodology. So well dome so far! I think you are right to feel uneasy about the method, because there are two different x-coordinates involved, in principle. The first dx is an increment in a coordinate system fixed in the cylinder (separation of ...

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The magnetic field caused by a magnet, like an electric field caused by charge and a gravitational field caused by mass, can only store energy. They can't create energy. The magnetic field can convert mechanical energy to electrical energy, but it requires a mechanical energy input. An example is moving a magnet through a coil of wire, or moving a coil of ...

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The rms value of an alternating voltage is a particular type of average. It is equivalent to sampling the the voltage at many equally spaced times throughout a cycle (getting $V_1$, $V_2$, $V_3$ ... $V_n$), squaring these values (getting $V_1^2$, $V_2^2$, $V_3^2$ ... $V_n^2$), finding the ordinary mean of these values: $$\text{mean square voltage} =\frac{V_1^... 2 A voltage can be induced in a conductive loop only if the magnetic flux through the loop changes. This can be done by a) a moving magnet or b) if you move the conductive loop which can't be done without some input energy. 1 In a circuit like you show, with a resistor connected to a power source by relativity short pieces of copper wire, the resistance of the wires is very small compared with that if the resistor, and the voltage drop across a segment of the wire would be close to zero. Most of the voltage drop occurs across the resistor. 1 RMS stats for Root-Mean-Square. You have a varying quantity, you then CALCULATE the Root-Mean-Square value of this varying quantity. The importance of rms value of AC is that, physically the RMS value of AC circuit is equivalent to a DC circuit that has voltage and current same as the rms values. 1 Sorry for my poor english. My native language is french. In the first case: the current being zero, there is no induced emf linked to a sudden variation in current. The capacitor retains its charge (which was the maximum charge during the oscillations). In the second case: you have a simple circuit (L, C) with the initial conditions q (0) known and i (0)... 1 Lightning generally initiates within a cloud or similar structure, due to charge buildup on its various constituents. Many lightning bolts pass harmlessly across the sky. The ground-sky static field can augment the local field and draw the leader downwards until it meets the ground. Rain has little effect. Consider scattering iron filings loosely on a sheet ... 1 Physicists simplify things to make a model that they can work with, so it could be ok to assume that the bee is a sphere. The reason the grain would be like a dipole, is that if the bee were positive, negative charge (electrons) in the grain would be attracted to the end near the bee, leaving the other end positive. The answers you would get from such a ... 1 It's the amount of electrical current that is dangerous. That is, only when the application of a high voltage results in a high current. High voltage usually will be more dangerous than a lower voltage depending on the resistance. This is due to Ohm's law$$I=\frac{V}{R} However, we can see that the the application of even a low voltage can result in a ...

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Your body’s resistance is roughly equal regardless of the voltage across it. (See note at the end.) Current goes according to Ohm’s law $V=IR$, so more voltage at fixed resistance means more current. More current is generally more dangerous, especially if it’s passing through you. Your original reasoning incorporates a fallacy that power is constant in this ...

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The rms voltage is a measure of the average voltage of an AC supply - it is not a different type of current supply. The rms or “root mean square” voltage is usually the value that is used to specify the voltage of an AC supply because: The actual voltage varies over time, at a rate determined by the frequency of the supply. The average or mean voltage is ...

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It would be pretty tough to manage a liquid with a large net charge: its self repulsion would tend to make it fly apart explosively. Basically you are describing a large capacitor. Capacitors are usually energized by pushing electric current through wires, not charged liquid through pipes. What you CAN do is store a bunch of positive and negative electric ...

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First assume extreme situations. The second magnet goes through the tube after the first one has left it. You clearly get two voltages. If you reduce the distance, you get overlapping peaks. You only get the full picture when you measure the power produced by the falling magnets. (By the way, I find it strange to call the measured voltage the EMF). Some ...

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This wikipedia article gives some useful equations for analyzing heat propagation. Note that it gives also a solution for heat distribution of a cylindrical wire. I think what might be complicating here is choosing the correct boundary conditions: is teh wire isolated from the external world? Is it losing the heat at the surface? How much of the heat is ...

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Breakdown depends on an 'Avalanche' taking place: positive ions formed by electrons being knocked out of molecules, and negative ions formed by the knocked-out electrons sticking to neutral molecules, are accelerated by the electric field. If they gain enough KE before colliding with other molecules they will cause more ions to be formed. These will also be ...

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