# Tag Info

2

The motion of electrons in the wires and the voltages can't be "seen" by naked eyes so the whole science of electric circuits is automatically "harder to visualize" than mechanics. But all such laws and phenomena have mathematically similar analogies in mechanics. The voltage is analogous – not only mathematically but physically – to the slope of an ...

2

Start by noting that the electrical potential is an energy per unit charge. In an electric field $E$ the field produces a force on a charge $Q$ of: $$F=EQ$$ so if we move the charge a distance $dr$ the work done is just force times distance or: $$W=EQ\,dr$$ The work done per unit charge is $E\,dr$, and this is what we mean by the change in the ...

2

It doesn't come only on one side. Suppose I define a new pair of constants $K_1$ and $K_2$, which obey: $$R = \frac{K_1}{K_2}$$ Then I can write: $$K_2V=K_1I$$ And I have a constant on both sides. For convenience, we usually just collect any constant values into a single constant, give it a name, ideally an intuitive one, and put it on one side. Which ...

2

Here is an answer I propose for the 2nd way. I'm for sorry for the bad paintings.

2

Your error is to assume that only your red charges generate the heat, ie the red charges go through area $A$ and they are not replaced by any other charges. If that were the case then the factor of $\frac 12$ would be correct. However as the red charges move through the resistor black charges to the left of the red charges would move into the resistor and ...

1

Since you equate $W$ with $NqU$, that means $W$ represents the amount of energy dissipated as heat during the time interval $N$ charges passed through the cross section. That time interval is $t / 2$, so the resulting power is $P = {{UIt / 2} \over {t / 2}} = UI$.

1

In the series connection the current (charge passing a point per second) is the same every where because there are assumed to be no sources or sinks of charge and so the charge is conserved - the amount of charge entering is equal to the amount of charge leaving. This is Kirchhoff's current law and there is certainly no accumulation of charge rather the ...

1

So, lets step back a bit. First lets look at avalanche breakdown. Electrons are constantly scattering, off atoms and other electrons, with some average scattering rate under given conditions. In a semiconductor, avalanche breakdown occurs when the field is strong enough that a free conduction electron gains (through accelerating in the field) a threshold ...

1

Charges at rest move when a force is applied on them and this is due to Newton's laws. Now to apply a force, we need a field, like electric/gravitational field. Each field acts upon certain measurable properties of a system, like gravitational on mass, electric on charge etc. Now potential is just a fancy name of height in electromagnetism. I hope you're ...

1

I'm don't know if you will find this answer satisfying, but suppose the EMF went the opposite way. Instead of opposing the current, it boosts the current. Then the higher current will produce a higher field and higher EMF which will boost the current, which will produce a higher field and higher EMF ... until the wire melts. Lenz's Law established ...

Only top voted, non community-wiki answers of a minimum length are eligible