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## Hot answers tagged electricity

6

Unless there is sufficient insulation (electrical impedance) between you and the earth when you touch a high voltage wire, yes you may get electrocuted. This is because most electrical power systems in the world are earth grounded (referenced to earth). The higher the voltage the greater the impedance to between you and earth ground needs to be. At 60 Hz it ...

5

To all future readers of this question: please be aware that the assumptions and statements made by @Martin Lowe in the question are substantially wrong, and believing them could lead to considerable safety risks for you or for any others who may interact with your residential electricity. So why are people still being told that they need to connect plug ...

5

The crux of your question seems to be this: One thing very very important that in this equation V refers to the potential of the resistor. Not the potential difference of the two sides. This seems to indicate some kind of confusion or misconception. There are not two different quantities of interest here, only one. People may sometimes loosely speak of "...

3

If you touch the wire and the ground at the same time, you close an electric circuit. This electric circuit starts at the power station, goes through the wire, through your body and into the ground. There are multiple parallel paths from there back to the power station, either directly through the ground to the power station or through the ground to one (or ...

3

You may not see the insulation. The copper wire in coils must be insulated (if there is no air gap), but that insulation is often a clear lacquer (historically shellac). For high temperatures etc, Kapton can be used as the insulating material.

3

You seem to be proposing that all series circuits have the same current. That isn't true. The equivalent resistance of a set of resistor in series is $$R_{eq}=\sum_iR_i$$ i.e. you just find the sum of all the resistances. If they are all ohmic then the current that flows through the circuit with voltage source $V$ is given by $$I=\frac{V}{R_{eq}}$$ ...

3

I'm pretty sure they are the same thing, so its simultaneous. Consider Maxwell's Equation: $$\nabla \times \vec{E}=-\frac{\partial\vec{B}}{\partial t}$$ Our Electric field has a non-zero vector derivative if we have a time varying Magnetic field. EMF is equal to the negative time derivative of the Magnetic flux: $$\epsilon=-\frac{d\Phi_B}{dt}=-\frac{d}... 3 Watch this video to realize that power lines, are dangerous for big birds, who span two of them at a time , and get electrocuted. Also fires may start this way, the bird may catch fire and transfer it to the dry grass underground. You have to realize what 3 phase power lines are. One wire carries no current and the other three each have a different ... 2 Thermoelectric effects, the Seebeck potential. But in metals it is very small, because temperature does not have much effect on the kinetic energy of the electron gas. It is much larger in doped semiconductors, where the electrons can be treated as a classical Drude gas. 2 You misunderstood the phrase "current remains constant in a series circuit". Consider the circuit below with a light-bulb and a resistor in series. In this circuit the current through the light-bulb is the same as the current through the resistor. This is meant by "the current remains constant in a series circuit". The current according to Ohm's law is:$$...

1

From Faraday's law, at steady state, $$\vec{\nabla} \times \vec{E} = -\frac{\partial \vec{B}}{\partial t} = 0$$ so since $\vec{E}$ is curl-free, it is the (negative) gradient of the electrostatic potential $V$: $$\vec{E} = -\vec{\nabla}V.$$ From the continuity equation and Ohm's law, at steady state and for uniform electrical conductivity \$\sigma = 1/\...

1

Note: I'm amending my answer after reading a comment from the OP that reveals (what I believe is) at the heart of the OP's question - a misconception of what is meant by "Resistors are used to reduce current...". Right,so if I use a battery with a high voltage which would then result in high current suppose 1.0Amps this could cause harm to a light ...

1

Yes, Trees are good insulators, and sometimes grounding is ignored if power lines are installed on trees. But still, they can break, and this phenomenon is called Electrical breakdown. this happens on high voltage, and high voltage is just what power lines are sending. So yes, current can flow, and if it flowed through the heart, you can even die.

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It's a transformer. The sudden rise/fall in current in the lightning strike generates a strong temporarily rising/falling magnetic field, which induces current in nearby conductors, like the metal shaft. The voltage could have easily been enough to shock you. That's why standing under a tree in a lightning storm is not good. If lightning strikes the tree, ...

1

Say, 10 charges flow through the wire per second, and suddenly they are slowed down at the resistor so only, say, 6 of them flow through the resistor per second. Where do the extra 4 charges per second go? They will have to wait "in queue" in front of the resistor. And every second 4 new ones arrive, so they accumulate and grow and grow in amount. Soon, so ...

1

A lot of this question seems to be a duplicate of the above questions, but this part seemed to be novel to me. So, when current which is basically electrons carrying electrical energy,when they pass through a resistor or lamp or any other electrical component some of the electrical energy gets converted into thermal energy,so the electrical energy they ...

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