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Questions tagged [batteries]

Devices to store chemical energy and convert it to electrical energy.

8
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2answers
6k views

Why is the voltage drop across an ideal wire zero?

I'm having trouble conceptualizing why the voltage drop between two points of an ideal wire (i.e. no resistance) is $0~V$. Using Ohm's Law, the equation is such: $$ V = IR \\ V = I(0~\Omega) \\ V = 0$...
17
votes
3answers
40k views

What happens when we connect a metal wire between the 2 poles of a battery?

As I remembered, at the 2 poles of a battery, positive or negative electric charges are gathered. So there'll be electric field existing inside the battery. This filed is neutralized by the chemical ...
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4answers
1k views

Voltage drop along an idealized resistance-free wire in a circuit?

If you connected the positive terminal of a battery to the negative terminal to a battery with a wire with (hypothetically) no resistance, and are asked to give the voltage drop of a segment of wire ...
18
votes
3answers
114k views

Different batteries connected in parallel

If we have 2 batteries one of emf x and the other is of emf y and we connect them in series we get an effective emf of x+y. But what if we connect them in parallel, how to calculate the emf now?
3
votes
3answers
4k views

Why electrons flow through a wire connected to a battery?

I would like to know why does electrons flow through a wire connected to a battery as said in AC/DC: What's the Difference?.It tells that "the electrons that are stripped from the carbon electrode is ...
2
votes
2answers
320 views

Battery charging a Capacitor

Ok I know there is a similar question already on here, but mine takes it just a step further. What I would really love to know is exactly how much energy is being transferred from a battery into a ...
15
votes
5answers
56k views

What is the difference between a battery and a charged capacitor?

What is the difference between a battery and a charged capacitor? I can see lot of similarities between capacitor and battery. In both these charges are separated and When not connected in a circuit ...
14
votes
4answers
14k views

Why aren't betavoltaics and alphavoltaics batteries widely used?

Betavoltaic batteries are devices which creates electricity from beta radiation of a radioactive material. Alphavoltaics operate similarly, using alpha radiation. The concept was invented roughly 50 ...
10
votes
1answer
4k views

What maintains constant voltage in a battery?

I know there's lots of questions that address similar situations, (Batteries connected in Parallel, Batteries and fields?, Naive Question About Batteries, and the oft-viewed I don't understand ...
6
votes
1answer
646 views

Why is the electric field created by a battery non-conservative?

Electromotive force(emf) or $\mathcal{E}$ is defined as $$\mathcal{E} = \oint \frac{\vec{F}}{q} \cdot \mathrm{d}\vec{s}$$ Here, $\vec{F}$ is the force which pushes the charges through a conducting ...
2
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4answers
10k views

Capacitor Charging and Discharging when connected to the ground

When we charge a capacitor using a battery and then remove the battery, the plates of capacitor becomes charged. One holds positive charge and the other one gets equal negative charge. o. k. ? Now ...
6
votes
3answers
11k views

Why is there no current flow when I connect two opposite terminals of two separate batteries?

I don't understand this..maybe there is something wrong with my understanding of battery or electricity. I am learning about electricity more deeply this time. So please spare with me. So lets begin ...
3
votes
2answers
2k views

How is potential difference maintained in a battery?

I am beginning of learn electricity so sorry if my questions are confusing or does not make sense. My question is specifically about how voltage (which I guess is due to separation of uneven charges) ...
3
votes
2answers
583 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 ...
2
votes
0answers
171 views

Estimating the battery capacity using current power consumption and battery percentage

I want to estimate the current maximum capacity (in kWh) having the current power consumption (in kWh) and the state of charge of the battery (in %) available in a time series. I do not have a full ...
1
vote
1answer
668 views

Meaning of a battery being 2.5 V

So this is a question with which I have been stuck for a while and it all revolves around the concept of volt. I have posted a LOT of questions on physics forums while trying to understand the ...
1
vote
2answers
5k views

Batteries in series vs parallel

As fa as I understand it, two identicle batteries in parallel will give double the amperage than just one battery and two batteries in series will give double the voltage. If my understanding is ...
15
votes
5answers
621 views

At an atomic level, what happens when you connect two batteries in series so that their voltages are added?

I can't for the life of me figure this out. I feel like i'm missing some crucial detail about how batteries work. Imagine two batteries connected in series, like this: ...
2
votes
1answer
8k views

Relation between Terminal Voltage and EMF of a cell while the cell is being charged

I know the relation between the terminal voltage, V and emf of the cell, V' while charging given by V = V' + Ir where I = Current in the circuit and r = Internal Resistance of Cell Can anyone ...
24
votes
3answers
8k views

Why do 'dead' batteries work again after exchanging the places of the batteries in an electronic device?

My camera, which is powered by two AA batteries in series, would not power on. I removed the batteries, exchanged their locations, and the device worked again - for another 15 minutes or so. The ...
3
votes
2answers
2k views

Emf of a Cell in an Open Circuit

Consider a cell having terminal voltage $V'$ and EMF, $V$ having internal resistance, $r$ and current, $I$ flows through the circuit in which an external resistance, $R$ is connected. Potential drop ...
2
votes
2answers
2k views

Will a battery connected to the Earth eventually deplete?

I've been thinking about this, and my answer is leaning towards yes, but I couldn't find any definitive answer by Googling. If the higher potential side of a typical battery is connected by wire to a ...
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vote
4answers
3k views

What is the difference between a circuit with a resistor and one without it in energy terms?

In Fundamentals of Physics (HRW), an equation is derived for the current in a circuit in terms of its emf and resistance by the 'Energy method'; that is, deriving $\epsilon = i \cdot r$ and saying ...
5
votes
1answer
16k views

short circuit an alkaline battery

i'm not doing anything related to physics, but i'm just curious : What really happen when i short circuit an alkaline battery ? some article in the net shown that fire/explosion can be happened when ...
4
votes
2answers
3k views

Why batteries in serial don't discharge each other?

A question that I've asked myself for long time about why batteries in series work as they do. I'll try to explain: If you take two batteries, let's say A and B, and you put A's anode touching the B'...
3
votes
3answers
7k views

Does the 'mAh' rating of a battery have something to do with its power?

I'm curious about the 'mAh' of a battery: how can this impact the power of the battery? I've done some research on the internet, and most of the articles I found explain about the 'amount of charge ...
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vote
4answers
119 views

How does resistance *really* work? (DC, battery, LED, atoms, electrons)

Backstory: I’m a software engineer just getting into electronics and it seems that everything I’ve ever been told about electricity my whole life is a candy-coated lie. I can’t find consistent logical ...
0
votes
2answers
316 views

If two batteries that are fully charged with opposite polarities and one has higher emf.Does one will charge the other? [closed]

if there are two batteries fully charged in a circuit connected in series and one has higher emf than the other does one charge the other or not ? does any current pass in the circuit ?and if yes ...
3
votes
1answer
10k views

How to determine direction of current mentally in complex electrical networks?

I wanted to ask, as stated above, how would one work out, by considering such thing as potential differences provided by the battery, the path of the current in a complex network such as given below: ...
3
votes
1answer
314 views

Analogy in combination of batteries in series and pn junction diode circuit to find potential difference

Can I use the analogy of combination of two batteries to get the potential difference between two points(by applying Kirchhoff's law) in case ,if a pn junction diode is used in the place of other ...
2
votes
1answer
272 views

Battery life with hot and cold wires

If a AA battery was kept at a constant temperature and was connected in a simple circuit will the battery drain faster if the wires are kept at a cold temperature or at a hot temperature? I ...
2
votes
1answer
520 views

How does a battery work and create a field inside it? [duplicate]

There is an explanation of how a battery works that says that inside the battery (in the positive charge convention) there is a field and the battery does work on the positive charge against the field ...
2
votes
1answer
135 views

How should one interpret $\vec{f}=0$ in an ideal battery?

In a circuit there are two forces that act on the charges to keep the current uniform through out,$\vec{f}=\vec{E}+\vec{f_s}$, where $\vec{E}$ is the electrostatic field and $\vec{f_s}$ is the ...
2
votes
2answers
62 views

From where electrons flow to make a bulb light?

Suppose we have the "basic" stuff like a battery 2 piece of wire and a bulb. Battery has a potential difference. But from where electrons flow to make the bulb light? from wire or from battery or from ...
2
votes
5answers
281 views

Many cells in parallel

If two or more cells of unequal voltages are connected in parallel (with the same terminal on the same side), is there a formula that gives the net potential difference? Also, by Kirchoff's loop law, ...
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2answers
124 views

Resistance of car battery

In my textbook, it is given that internal resistance of a car battery increases with decreasing temperature. But car batteries contain lead, which is a metal, and hence the resistance should decrease. ...
0
votes
3answers
8k views

How is Capacitance affected by a seperation distance and with or without a battery?

The questions specifically says this : A parallel-plate capacitor initially has capacitance $C$. The distance between the plates is then doubled, with a $9.0V$ battery connected. The battery is then ...
0
votes
3answers
1k views

Capacitors in parallel final potential difference

I was provided with the following problem. So I first calculated the total capacitance for (i), which was $$4.5 + 1.5 = 6.0 \mu F$$ Now part (ii) is the question i'm struggling at. I know that ...
0
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3answers
68 views

Case where potential difference causes no current

why current will not flow from battery if I connect positive terminal of battery to ground even when there is potential difference
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5answers
2k views

Can a capacitor be charged without having resistance in the circuit?

I was looking for the fact when a capacitor is directly connected to battery without resistor what will happen? If possible then tell the time for charging.
0
votes
1answer
84 views

Why do we use the term “voltage” for a battery?

Voltage or potential difference is the difference of potential energy of two points in space per unit charge in an electric field. A battery creates an excess in electrons in one side and a lack in ...
0
votes
1answer
965 views

Emf Independent of External and Internal Resistance

Suppose a cell having emf, V and terminal voltage V' having internal resistance, r connected with an external resistance, R in the circuit in which current, I flows. We know that V=V'+Ir Can anyone ...
0
votes
3answers
232 views

What is the voltage at every pair of points along a ideal wire that is connecting the two terminals of a battery?

If you stick a wire across a battery, obviously it is going to discharge the battery. This will be due to a voltage difference between the two terminals. However, the equation $V = IR$ tells you how ...
0
votes
1answer
1k views

EMF of an ideal cell

I know it's a very stupid question but I am confused a little bit right now. An ideal cell has constant EMF of 7V. When connected in a circuit, the voltage across the cell decreases to 5V. Can i say ...
0
votes
3answers
105 views

Could this open electric circuit work?

Two batteries are interfaced by a resistor. Parameters such as resistance can be set arbitrarily. Does it work?
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2answers
362 views

Batteries connected in Parallel

"If we connect two batteries in parallel, the battery with higher voltage will discharge into the other one." What is the intuition behind this?