All Questions
Tagged with electricity electric-current
115
questions
11
votes
7
answers
21k
views
Difference between current and voltage sources
I am confused about the current and voltage. My intuitive example would be that of a pipe of say water. The diameter of the pipe determines the amount of water flowing per second but the pressure is ...
- 211
10
votes
9
answers
3k
views
How does the current remain the same in a circuit? [duplicate]
I understand when we say current, we mean charge (protons/electrons) passing past a point per second. And the charges have energy due to the e.m.f. of the power supply.
Now tell me, if a lamp has ...
- 340
10
votes
2
answers
74k
views
How can be the neutral wire at 0 volts when current flowing through it?
Voltage is potential difference, and current flows because of voltage. So if the voltage is zero, how can current flow through the neutral wire.
- 181
9
votes
5
answers
4k
views
How does the speed of electricity become the same as the speed of light?
"The field due to the battery sets up a surface charge in the wire. The surface charge is negative near the negative pole of the battery, and positive near the positive terminal, and varies more ...
8
votes
5
answers
22k
views
Getting Deep into Drift Velocity
We know for a metallic conductor
Current $\frac{I}{enA} = v$ where $v$ is drift velocity , $e$ is the charge of an electron, $n$ is no of electrons per unit volume and $A$ is area of cross section.
...
7
votes
3
answers
21k
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Questions about voltage
For some reason, I feel like the concept of voltage is escaping my grasp. I've done much research on these forums and through texts, and come across answers that seem quite well thought out, but still ...
- 909
7
votes
4
answers
48k
views
Why don't we get a shock touching neutral wire?
Neutral wire has a V same as ground i.e almost 0. Also it carries some current. So if we touch the wire don't we to become a part of the circuit? Even if we are on the ground and current should flow ...
- 103
6
votes
3
answers
40k
views
How exactly does a resistance reduce current?
I've heard that resistors are used to decrease current to a particular appliance, such as in the regulator of a fan. However, I've also heard that the total current in a circuit is always the same- in ...
- 219
5
votes
1
answer
3k
views
Can conductor be charged?
I have a copper conductor. For a while, I apply a voltage of $12kV$ DC from a source. After removing the source, will the conductor stay charged from the source if is not earthed? Will it discharge ...
- 185
3
votes
1
answer
1k
views
Why is the anode (+) in a device that consumes power & (-) in one that provides power?
I was trying to figure out the flow of electrons in a battery connected to a circuit. Conventionally, current is from the (+) terminal to the (-) terminal of the battery. Realistically it flows the ...
- 133
3
votes
1
answer
5k
views
What is the difference between electric spark and electric arc?
In my student book they separate these two and indicate that sparks need high voltage to occur while arcs need low voltage with normal or low pressure and electric arcs CAN come with heat and bright ...
- 59
2
votes
4
answers
5k
views
Why electrical resistance decreases with cross sectional area?
With increase in cross sectional area the number of atoms with which electrons will collide will also increase in the same proportion. So basically the resistance shouldn't change with increasing wire ...
- 33
2
votes
2
answers
710
views
Battery and current confusion?
How exactly does a battery produce a current in the circuit connected across its ends? I dont want to know the chemical reactions in the battery core, but just the essence of it. I believe it doesn't ...
- 3,148
2
votes
2
answers
500
views
Direction of magnetic field around a straight current carrying wire
I am currently studying for O Level and I have been learning about electromagnetism for the past year. The topic has never clicked for me because I've never been taught the true relationship between ...
- 123
1
vote
5
answers
2k
views
Field inside a wire?
This answer gives a great explanation of why the field inside a wire connected to a battery must be equal at all points: Why doesn't the electric field inside a wire in a circuit fall off with ...
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