All Questions
39
questions
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The temperature of a metal wire rises when an electric current passes through it because- [closed]
The options given were-
A)Collison of conduction electrons with each other releases heat energy
B)When the conduction electrons fall from higher energy to lower energy level heat energy is released.
C)...
0
votes
1
answer
61
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Why do we indicate current to be flowing against electrons in a electric circuit ? If it is a convention thenwhy do we draw it along studying it? [duplicate]
I believe that electric current is a kind of force (even when we consider it to be opposite to the flow of electrons). If it is so then what is the nature of this force ? And also tell me if there are ...
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
1
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0
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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 ...
- 21.3k
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4
answers
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
2
votes
3
answers
66
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How does the actual power of the device depend on the angular frequency of the voltage? [closed]
The voltage source produces a sinusoidal AC voltage. An electrical device with resistance and inductance is connected to the source. How does the actual power of the device depend on the angular ...
user331916
0
votes
1
answer
75
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Relative Amplitude: Current at full brightness [closed]
What is the relative amplitude of the flow in the filament of a miniature lamp the instant power is applied in comparison with the current at full brightness?
a. High
b. Low
c. The current is the same ...
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votes
1
answer
89
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What's the magnetic field produced by a current carrying circular loop at a point on its plane?
How do I find the magnetic field in this case? I already know about the magnetic field produced by a current carrying loop at an axial point or center but what about the point on its plane?
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-3
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2
answers
49
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What happens (from the first principle perspective) when you connect 2 negative terminals in a DC Circuit? [closed]
E is the electromotive force, r is the internal resistance.
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1
answer
175
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Value of current in the given circuit [closed]
Since, point B is connected to Ground, Should not current exist only in the branch ABG, and zero current in the branch BCDE, as current chooses least resistive path to move to lower potential.
...
- 439
-1
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1
answer
113
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Why, when an electromagnet is connected to a circuit, does the electric current not reach the required strength immediately, but gradually? [closed]
When an electromagnet is connected to a circuit, the electric current does not reach the required strength immediately, but gradually. Why?
When the battery terminals of the flashlight are briefly ...
1
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2
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3k
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Transformers: How does current in primary coil change?
I was doing a question on transformers and found this really confusing question:
A 100% efficient transformer converts a 240V input voltage to a 12V
output voltage. The output power of the ...
- 11
2
votes
3
answers
146
views
Flow of charges
I saw this question which asks for the condition for flow of electricity through the conductor i know that electricity will flow only when there is a potential difference achieved between the ...
- 1,200
0
votes
2
answers
468
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Direction of current flow in circuit with multiple cells
As the point $A$ is earthed we know that its potential is zero, same is true for point $B$. Due to the cell between $B$ and $C$ we can say that potential at $C$ is $-3V$. So the potential at point D ...
0
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1
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731
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Rate of energy dissipation in a wire carrying current cut in half [closed]
In my physics textbook, I have a sample problem stated as follows:
You are given a length of Nichrome heating wire; it has a resistance R of 72 Ω. At what rate is energy dissipated in each of the ...
