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Conservative and non-conservative electric field due to to changing magnetic flux

"Is there a conservative electric field induced?" Yes, I think so. The magnetic field, directed into the page and steadily increasing in time, generates a non-conservative electric field in ...
Philip Wood's user avatar
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1 vote
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Current density and units

Volumetric Current density is typically the amount of current per area flowing through a cross-section. Since current is a word for charge-per-time, current density is charge-per-time per area. In SI ...
Steeven's user avatar
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1 vote

Current density and units

These are the physical dimensions, since a current density is defined as the product of a charge density and the average velocity of the charges, namely $$\mathbf{j} = \rho \mathbf{v} \qquad , \qquad \...
basics's user avatar
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0 votes

Current density and units

According to your comment, $\vec{\lambda}$ has simply the dimension of current. It is a linear current produced by a line charge with a line charge density, not a "linear current density". ...
freecharly's user avatar
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1 vote
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Direct Current through a Copper Tube - Magnetic Field Question

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Frobenius's user avatar
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1 vote
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Why does the stopping potential correspond to zero current?

Your intuition would be right, if the circuit used in photoelectric experiments were closed. That is to say, in a closed circuit, it doesn't matter in which way the electrons flow, we will always ...
Lagrangiano's user avatar
0 votes

Voltage drop and current across a resistor in a DC-circuit

As far as I can see, the current would be 6A, since the current would always travel along the path of no resistance, essentially eliminating the 8-Ohm resistor There is your error.
Farcher's user avatar
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Can an inductor increase circuit current?

The circuit you're searching for is called a buck converter. It cyclically switches current going from its power source into to an inductor while continuously drawing current from the other end. The ...
John Doty's user avatar
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Can an inductor increase circuit current?

Can an inductor increase circuit current? The short answer is no for the situation you describe. The inductor resists a change in current. So when the circuit breaker opens the inductor produces a ...
Bob D's user avatar
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-2 votes

Can an inductor increase circuit current?

Since you open the circuit, you don't have any current, just high voltage by breaking fast.
trula's user avatar
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3 votes

What is the area of a resistor?

The area you ask about, is the cross sectional area of the resistor and is the cut area you get if you literally cut the resistor in half orthogonal to direction the current flows. For example if the ...
KDP's user avatar
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2 votes

What is the area of a resistor?

In the context of resistors and electrical resistance, "area" usually means cross-sectional area - for example, a wire with a circular cross-section and diameter $D$ will have a cross-...
gandalf61's user avatar
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4 votes

Direct Current through a Copper Tube - Magnetic Field Question

That there is no magnetic field inside a circular conducting tube due to a rotationally symmetric dc current flowing in it, follows directly from Maxwells equation in its integral form (Amperes law): ...
freecharly's user avatar
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General Form of the Biot-Savart Law for anywhere on the $x$-Axis

The $\bf B$ field on the axis a distance $\bf d$ above a loop is given by \begin{eqnarray} {\bf B(d)} & = & \frac{I}{c}\oint \frac{[{\bf dr'}\times{\bf (r-r')}]}{|{\bf r-r'}|^3}\nonumber\\ &...
Jerrold Franklin's user avatar
-1 votes

Forces on an elliptical current-carrying Loop

I'd say yes. Imagine the ellipse is deformed until it's a rectangle with a longer length $L'$, and a constant small spacing $W'$. This now looks like two wires close to each other, with opposite ...
Ric's user avatar
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0 votes

Zero Shunt Resistance in Ammeter

Think of an ammeter as a voltmeter measuring a voltage $V$ across the resistance of the ammeter $R$, ie $I = \dfrac VR$ and the deflection of the needle, $V$, is calibrated in amps. Adding a shunt, $...
Farcher's user avatar
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I'm getting different values for the calculation of voltage drop across parallel resistors than I am for the summed voltage drop. How do I fix this?

The voltage across each resistor, and the parallel combination, should all be the same (2 Volts as you calculated). For parallel resistor circuits, like what you have shown, one does not sum the ...
ad2004's user avatar
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2 votes

Zero Shunt Resistance in Ammeter

If I understand your question, placing a shunt resistance of zero Ohms in your circuit would make the voltage drop across the ammeter zero (which I'm defining as the galvanometer + resistance of the ...
ad2004's user avatar
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Confusion about EM waves in a conductor, AC in wires, and skin effect

The important fields are not inside the wire. They're in the space around the wire, usually either between the wire and ground or between one wire and another wire in a transmission line. Since the ...
The Photon's user avatar
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Will I get shocked touching the hot wire in these cases?

The reason the neutral is grounded is that there is generally significant leakage of current from primary to secondary of the utility's step-down transformer, driven by the high primary voltage. ...
John Doty's user avatar
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1 vote

Will I get shocked touching the hot wire in these cases?

... However, as I understand, the current will always choose the least resistant path to go back to the source. In this case, it is the path through the neutral wire and not through my body (because ...
KDP's user avatar
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1 vote

Will I get shocked touching the hot wire in these cases?

Case 1: neutral is not grounded. Touching the hot wire causes a load (human body) to be connected from hot to earth. Since there is no connection to earth of the electrical supply, then in theory the ...
Fabio Barone's user avatar
0 votes

Will I get shocked touching the hot wire in these cases?

Case 1 has no conducting path (only a bit of capacitive current might flow if it is AC, so you might at most feel a small tingling). Case 2) in your description has only one path, through your body, ...
Jos Bergervoet's user avatar
-2 votes

If the earth is negatively charged why is lightning striking it?

Yeah, important potential differense instead of just negative or positive charge. Little bit strange example, 2 guys are carrying some baggage. One with very heavy package and another with light weigh....
TeMaToS's user avatar
1 vote

Why is my voltmeter reading the supply voltage instead of load voltage?

If your voltmeter appears to be reading exactly 5.0V while delivering current to the 100 ohm resistor, it means the internal impedance of the power supply, which is in series with the 100 Ohm resistor,...
Bob D's user avatar
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5 votes
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Why is my voltmeter reading the supply voltage instead of load voltage?

You are right to be concerned, but in this case the voltage across the resistor is 5.0 V Commercial voltage supplies are engineered so that they can provide the rated voltage over a wide range of ...
garyp's user avatar
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0 votes

RC discharging equation/natural response

Indeed you are right with your two equations: $$\begin{align} i_C+i_R&=0\\[5pt] \Rightarrow C\frac {dv}{dt} + \frac1R v &= 0 \end{align}$$ And if we proceed from there we get: $$\begin{align}...
Jos Bergervoet's user avatar
-1 votes

RC discharging equation/natural response

Why do we make this particular assumption when trying to derive the capacitor discharging equation/rc natural response? You can choose whatever direction you want, just make sure that the voltage and ...
ioveri's user avatar
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1 vote

Energy lost in a resistor and its temperature

Of course, yes, but if you could raise voltage and keep current constant. But according to Ohm's law, by increasing voltage, current will also rise and this is why the effect of rising voltage doubled....
mohammadsdtmnd's user avatar
4 votes

Unable to Understand How Current Divides in Parallel Circuits

Reduced to basics it should be clear. (For some values of should be :-) ). Vsource = input voltage. Vn = Voltage across N. Vm = voltage across M Rldr = resistance of LDR. Ohms law says : I = V/R So, ...
Russell McMahon's user avatar
6 votes

Unable to Understand How Current Divides in Parallel Circuits

I think your underlying misconception (a common one at that) is that you think of voltage sources as current sources. A voltage source supplies a specific voltage. The current it supplies depends on ...
Vercassivelaunos's user avatar
4 votes
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Unable to Understand How Current Divides in Parallel Circuits

Current going through a branch in a circuit divides, with more going to branches of less resistance. This part of your reasoning is correct. What you failed to account for is that the current being ...
HTNW's user avatar
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1 vote
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Why does current lag behind voltage by 90° in an inductive circuit?

Because in a periodic sine function a phase of +90° is identical to a phase of -270°. You usually take the smallest value.
freecharly's user avatar
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2 votes

Why does the phase difference of the capacitor voltage change with AC frequency?

The capacitor possesses an impedance which decreases with increasing frequency. At zero frequency it is an open circuit and at high frequencies it is a short circuit. In combination with the ...
niels nielsen's user avatar
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Zener diode reverse bias I(V) equation

In principle, the current voltage characteristic of an ideal reverse bias Zener diode is determined by tunneling of electrons through the triangular energy barrier formed by the band gap and the large ...
freecharly's user avatar
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Drift current and diffusion current in depletion region of diode at equilibrium

The Shockley diode current-voltage relation assumes that both the total electron and the total hole current through the diode is determined by their diffusion currents at the respective edge of the ...
freecharly's user avatar
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2 votes

Derivation and theory for $I = kV^n$

For temperatures up to a few hundred kelvin, the resistance of a metal wire is roughly proportional to its kelvin temperature, $T$, so $$R=\alpha T,\ \ \ \ \ \text{that is}\ \ \ \ \ \tfrac VI=\alpha T ...
Philip Wood's user avatar
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