All Questions
Tagged with electricity electric-current
791
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Current by change in position of charges
I have been thinking about the idea given below
Consider the following situation
I have a rod which has a mass $m$ and hence does have the virtue to perform work against the gravitational field of ...
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1
answer
33
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Analysis of Current for infinitesimal time
Suppose we have a hydrogen atom and electron is revolving in a orbit around the nucleus. We have to find current due to the revolving electron.
Current = ev / 2πr
( e = charge of electron)
( v = ...
- 109
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2
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38
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Mobility (Current Electricity)
I was reading mobility in current electricity and there it was written that the direction of conventional current due to positive and negative current carriers is in the same direction but I cannot ...
2
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2
answers
127
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Is it necessary for circuit to be closed in order for current to flow?
In case of earthing, we attach a single wire to the earth and if some residual electrons remain in the instrument they flow to the earth until the potential of the instrument also becomes Zero. So if ...
- 187
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2
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56
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Moving charges in a circuit [duplicate]
Current flow from positive to negative terminal in a circuit. But the charges which are moving in the circuit are the electron that is moving from the negative terminal to the positive terminal. Why ...
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2
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57
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Current in a two capacitors system in parrallel
I solved this question and I got the values of charges on capacitors in figure B. But my question is charge on capacitors is getting redistributed,but how is it possible when potential difference ...
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27
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Can you measure different currents at different contact points for a volume of material made of two different metals with different conductivities?
My question is about the variation of conductivity in a volume of material and its effect on measured current. A volume is comprised of two metals joined symmetrically in a cuboid shape as in the ...
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2
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185
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Explanation of Potential Difference
My question is to verify if my thought process below is correct.
So in a circuit the charge will flow (the current). When the charge flows there is resistance which is the collisions of the charge ...
- 37
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1
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68
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Current flow with no resistance
Imagine a simple circuit consisting of a battery with potential $V$ connected to a resistor with resistance $R$ by a loop of copper wire with $0$ resistance. It is obvious that a current $I=\frac VR$ ...
- 366
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2
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207
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Does current flow equally through the cross section of a wire in DC?
(Most Probably a duplicate, but I couldn't find it)
I have heard about 'Skin Effect' in AC, but currently Im only and only concerned about DC.
When current flows in simple DC circuit, does the current ...
- 1,305
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119
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Why won't the bulb light? [closed]
Here's what the marking scheme says: "Capacitor gets charged first and acts as an insulator/blocks current".
However, electrons flow from negative to positive, so shouldn't the electrons ...
- 93
1
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2
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92
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Energy conversions in Electric furnace
Heating furnaces use eddy current to work, but I have a problem understanding something, what are the energy conversions that happen in the electric furnace? Is it magnetic->electric->thermal or ...
- 17
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1
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129
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Effect of solenoid on iron core in ac and dc circuit [closed]
If i have 2 insulated coils and i wrap each one of them on a iron core (i have 2 seperate ciruits) if i add a dc source “battery” in the first circuit and an ac source in the second circuit would ...
- 17
0
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3
answers
102
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Potential drop against internal resistance of cells in combination
Suppose two cells of emf and internal resistance e1, r1 and e2, r2 respectively are connected in series. The negative electrode of 1st cell is connected to negative electrode of the second cell. Why ...
- 1
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2
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76
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WIll maintaining the ratio of 'Voltage/Resistance' violate Ohm's Law?
In an ohmic conductor if voltage and resistance are increased in a constant ratio, the current will remain same and if it remains same, won't it violate the Ohm's Law?
As because Ohm's Law states '...
1
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2
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50
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Why doesn't coil in an Ac generator not get deflected in accordance to the flemming's left hand rule when current starts to flow through it [closed]
Why doesn't coil in an Ac generator not get deflected in accordance to the Flemming's left hand rule when current starts to flow through it.
When the coil is ...
0
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1
answer
26
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Do attracted to electrode charged particles make current?
Consider a bulb with an anode. Cathode, is out of bulb.
Bulb is filled with gas.
Now, gas molecules are ionized by, for example external radiation.
Bulb should now contain "free" electrons, ...
- 361
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1
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36
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Current in a Nonuniform Diameter Wire
According to the text Current depends on Area, but then in problems with a "nonuniform diameter" we say that the Current does not change even though the Area changes.
I think I understand ...
1
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1
answer
147
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How do electric fields in circuits exactly work?
I have been introduced to circuits and told that an electric field, along with a emf provided by an external source (which can't be electrostatic), causes electrons to move. They follow the direction ...
1
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0
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47
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Resistance across different terminals of a material of variable resistivity [closed]
I have seen many questions in my book trying to find Resistance across different materials of variable resistivity(by integration).
For example, consider the following :
I can find resistance across ...
- 265
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2
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91
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Current returning to wire when passed through earth
Consider the following circuit:
I have a bulb connected to a battery and then the wire as shown is earthed from two points. Now, since across the bulb potential difference will be zero, no current ...
- 265
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1
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87
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Hysteresis phenomenon on a tungsten filament
I have a lamp with a standard filament bulb. A dimmer allows to modulate its intensity. It's an old low-end dimmer, so I assume it's a potentiometer that regulates the current in the bulb.
When I vary ...
- 101
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3
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Does current make the full return trip?
In an AC system, the neutral wire is said to provide a return path for the current back to it's source. Given that the current is said to be alternating back and forth, how does this work, does the ...
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1
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39
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When using a screwdriver tester i am completing the circuit with 110v?
if i use a screwdriver tester, i am part of the circuit with 110v passing my body? isn't this dangerous?
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"Why do power lines use high voltage?" Loss in power equal to Current*Voltage? [duplicate]
I define P is the average power. So $P=IV$ and $I=\frac{P}{V}$.
$P_{loss}$ I define to be the power loss, which is equal to $I^2R$.
Substituting for $I$, $P_{loss} = \frac {P^2R}{V^2}$
So I get that ...
- 93
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75
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How large a current is realistic for a mains wire? [closed]
I recently encountered this elementary physics question:
A mains wire outside your house is $15m$ above the ground. The power company says the voltage is $10 kV$, and the wire delivers $18 MW$ of ...
- 21.4k
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4
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84
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About electric field and electric potential
We know that electric potential is the negative of work done by electric field in moving a unit charge from infinity to that place.
This statement shows that electric field causes a potential ...
- 105
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2
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32
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Will a circuit be closed if we make a 100% efficient LED?
Suppose we make a LED that is 100% efficient, that is, it converts 100% of electric current we supply to light. Based on my understanding of electric current, as there is no current flowing back to ...
- 419
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71
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Is drift velocity directly or inversely proportional to the length of the conductor?
One way that drift velocity can be represented is: $$v_d = \frac lt$$
$$\Rightarrow v_d \propto l$$
However, another way it can also be represented is:
$$\begin{eqnarray*}
v_d &=& \frac {I}{...
- 419
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3
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142
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What exactly is electric current?
In my textbook, Current is defined as the rate at which charge flows through a given surface (cross sectional area). These are my questions:
How can there be current through a given cross sectional ...
