# Tag Info

4

It's not a fundamental feature of electrical potential, but: If you have a polycrystalline metal and you cut and polish a smooth surface, the differently-oriented regions will present a different lattice plane to the outside. Crystals cut along different planes may have slightly different work functions, and so the electric potential very close to such a ...

0

This is because what changes in each resistor is the current passing through and not the voltage difference. One the other hand when resistors are in series they have the same current passing through, but different voltage through each one's nodes. In essence when resistors are in parallel do not share same current path (i.e wire) but share same voltage. On ...

2

Kirchoff's laws tell us that the potential drop across any closed loop in a circuit must be equal to the voltage sources in the loop, from which we conclude that the voltage drop across resistors in parallel must be equal. Ohm's law states: $$V=IR$$ From which we conclude that, since $V$ is fixed, if the different resistors have different $R$'s, then the ...

14

For static charges, the relationship is V (voltage) = Q (charge) / C (capacitance). Capacitance is a function of the shape, size and distance between objects, which are all continuous values. (Well, I suppose you could argue that shape and size are quantized to the atomic spacing of the object's material, but you can't say the same thing for distance.) So ...

7

Voltage is a continuous function. If you are a certain distance from a (point) charge $q$, the potential is $$V=\frac{q}{4\pi\epsilon_0 r}$$ By adjusting the value of $r$ to anything you want (not quantized), you can get any potential you want. And so yes, when you do any analog-to-digital conversion, you will "destroy" a certain amount of information. ...

5

Voltage doesn't come directly from the charge of the electron. It's the energy per charge. The charge carriers may be discrete, but the energy is not. We can easily generate a potential by moving a wire through a magnetic field. The potential is proportional to the speed of the wire, which is a continuous value. $$V = vBL\sin{\theta}$$

0

Supposing that the charger gives the voltage greater than 12 V (say, 15 V), we can estimate 15 V × 100 A = 1500 W, a power of a small electric kettle. It is insufficient to effect an actual explosion quickly, but the battery will possibly immediately start to spew the acid mixed with hydrogen bubbles (note that hydrogen is flammable). Another question in: ...

1

The 2nd equation defines the ideal inductor circuit element. It is understood that the voltage $v$ and current $i$ in that equation are the voltage across and current through the inductor. The inductor emf is the opposite sign of the inductor voltage. $$\mathcal E_L = -v_L$$ Clearly, when the current 'stabilizes' (the time rate of change of the inductor ...

0

The voltage across the battery when there is zero current (no load connected) is called the open circuit voltage. The emf of the battery is equal in magnitude to the open circuit voltage. I'm not certain that there is a standard term for the battery terminal voltage when a load is connected since, in general, this voltage varies with the load. One might ...

1

DC signals do not induce electro-motive forces, for you would need a change in the magnetic flux through your circuit which can only be achieved with a time-varying current (resulting in a time-varying magnetic field). This, of course, assuming that your circuit is stationary, so basically you are not moving the wire around for this would change the area ...

0

I'm not sure what you are asking, but I'll address one point. Ohm's Law, like many other physical laws, is an idealization. It applies only to ideal systems, and ideal systems do not exist. But Ohm's Law is useful because it accurately describes a very large class of real systems. Even for systems within this class it is only an approximation. One will ...

2

The resistivity of any material is related to the mobility of the charge carriers within it by: $$\rho = \frac{1}{ne\mu}$$ where $\mu$ is the mobility, $e$ is the electronic charge and $n$ is the number density of charge carriers. I've deliberately used the term charge carriers rather than electrons because in semiconductors like diodes the carriers can ...

0

For a constant resistance Ohm's Law is $$V = IR.$$ Now, it happens that it's pretty easy to make a constant-resistance device (we call them "resistors") and that it's easier to make constant-voltage devices than constant-current devices. So most of the circuit problems we encounter have a constant-voltage device like "a wall socket" or "a battery" or "a ...

0

Ohm's law can be summarized as this: The drop in electric potential (voltage) across a section of a circuit is equal to the total current flowing through that section of the circuit multiplied by the total resistance of the section of the circuit. By that law, if you have a current flowing and there is some net resistance, there will be a drop in voltage. ...

0

Paschen already did. See Paschen's Law

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