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Questions tagged [batteries]

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

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78 views

Why does the full PD across a battery manifest itself across a break in a circuit at any point?

Consider the following circuit: I want to know why the full pd of the battery can be measured across the break if a voltmeter was connected. Surely when the whole circuit was closed the charges at ...
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2answers
76 views

Charging a battery

So we have a charger outputting V volts and $I$ Amperes and two rechargable batteries of the same capacity $Q$ coulombs but different emf's $V_1\&V_2$. Which battery would charge faster? ...
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1answer
30 views

DC Battery Charging Question

I have a 7.4v LiIon that hold 1450ma. I have a variable DC bench power supply that I can crank up or down and adjust as needed. I want to quickly charge the battery and noticed if I adjust the ...
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3answers
44 views

Does current get divided between single cells or only through parallel connections?

So let's say I have 2.5KW motor that runs at 48V, drawing peak around 55A. Let's also say that I have an 18650 battery bank, which consists of 13 batteries in series, to give me 48V, and 4 parallel ...
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2answers
69 views

How could a bulb light up if aĺl the voltage is lost in the resistor?

I recently came up with this slight confusion about voltage loss in resistors/resistance. So for example My circuit has a 12V battery, a 2 Ohms resistor and a Bulb. If we use the V=I.R formula then a ...
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2answers
324 views

How does the internal resistance of a cell vary with temperature?

Does anyone have a physics explanation to why the internal resistance of a battery decreases as the temperature increases?
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6answers
12k views

Why do we use capacitors and not batteries in defibrillator?

Why do we use capacitors in defibrillators and not batteries? I know that capacitors are used to store electrical energy but isn't the function of a battery just the same? Moreover, I know that ...
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2answers
514 views

Galvanic Cells and Electric Potential

In a battery or a galvanic cell, the electric potential of the battery is due to a difference of charges between the two cells like in a capacitor? So it is the electric field due to this separation ...
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1answer
30 views

What is the potential difference inside a metal conducting wire?

When a conducting wire is connected to a battery, potential difference is set up inside the battery. But, what is the case of a simple conducting wire which has free electrons inside it(without ...
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1answer
396 views

Electric field created by a battery

If I create an electric field using a battery between two parallel plates and leave the battery connected, will the electric field always exist for as long as the battery lasts, including normal self ...
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3answers
416 views

Charge density in wires [closed]

I have a very simple circuit, composed of a capacitor and a battery with constant $V$. The wires that connect these two components allow the capacitor to gain a voltage V ( the same V of the battery). ...
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2answers
516 views

RC circuit discharging capacitor, trouble understanding

If we apply loop rule while charging the circuit we get: $$\varepsilon -iR-\frac{q}{C}=0$$ The way I understand, we follow trough the circuit just before the battery, as we move trough the circuit ...
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3answers
1k views

Why is the emf over an inductor equal to that of the battery? [duplicate]

In a hypothetical circuit with only an inductor and a DC voltage source (no resistance), why is the voltage across the inductor the same as the source voltage? I get that the charges coming from the ...
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3answers
5k views

When potential difference is equal to the emf, isn't the current 0?

I have been told that the $emf$ is equal to the potential difference across the terminals of a cell when no current is flowing. Does that mean that the current is zero ($I=0$)?
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2answers
31 views

Conductors in electric circuits And electrostatics

I know from electrostatics that electric field inside a conductor is zero. I also know that there must be electric field inside a conductor carrying current in electric circuits. I am confused.
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1answer
52 views

Why can you assume the current remains the same after changing resistance?

In my physics textbook there is a question about a circuit: In question b) We find out the current in the circuit is 0.003A. This is before the voltmeter is added. In question c) a voltmeter is ...
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1answer
56 views

Creation of electric field inside a conductor

My book says that as soon as the two ends of a conducting wire touches the two terminals of a battery, it generates an electric field inside the conductor. Why?
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3answers
532 views

Why can't we add the emf of two batteries in a parallel circuit?

My teacher told me that two batteries' emf cannot be added in a parallel circuit but can be added in a series circuit. However I can't seem to fully grasp why and I think there may be some loopholes ...
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1answer
66 views

Why does a battery powered radio's volume go down as batteries age, even when the batteries' voltage is constant?

A set of batteries are used for a long period of time. Explain why the volume of a radio is low even though the voltage of the batteries is the same as when they were first bought.
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1answer
224 views

Factors affecting Battery Voltage

How do batteries produce a certain voltage, such as 1.5V or 9 V? From what I understand, battery EMF comes from oxidation of the anode, which releases electrons that can flow through a circuit. But ...
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4answers
149 views

Capacitors' working in a circuit

Does charge in a capacitor containing circuit stop flowing when the potential of the capacitor becomes equal to the potential of the battery??
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5answers
642 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: ...
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2answers
43 views

Ideal Capacitor (Introductory Physics Question)

If I have a simple setup of a open circuit with a battery (constant battery) , resistor, and uncharged capacitor, and then I close the switch of circuit, and keep it closed until the capacitor is ...
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2answers
121 views

Why can't I series 5 D Cell Batteries to achieve 7.4 volts?

I appreciate this site that is allowing me to get an answer to a phenomena I am witnessing. I'm trying to series 5- D Cell Batteries. However I cannot make it completely through because the middle ...
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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 ...
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1answer
5k views

Factors affecting the internal resistance of an electrolytic cell

How does the internal resistance of an electrolytic cell (a source of emf) depend on I) the concentration of the electrolyte? II) the temperature of the cell?
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1answer
41 views

Voltage is changing. Then why do we use a constant value (if given as battery is 3V)in doing sums.?

Actually the potential difference changes throughout each part in a circuit and the electrons dont have the same energy (say the battery is 3V) throughout the circuit.then why ,when do we use V=3V as ...
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1answer
54 views

What does it mean for a battery to be 1.5 Volt? [duplicate]

What does it mean by a battery is of 1.5 Volt ? Does it mean that it would take 1.5 Joules of energy to transfer -1 columb of charge from the negative end to the positive end of the battery ? What is ...
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2answers
61 views

How are electrons in a circuit doing work?

When electrons flow through a circuit, I don't understand how we can hook something up to the circuit (like a bulb or anything else) and have it receive power / do work. Most tutorials gloss over ...
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1answer
711 views

Voltage drop across battery with internal resistance

Consider a battery with internal resistance connected to an external voltage source; there is a voltage difference along the battery The voltage source is not drawn in the picture The voltage ...
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3answers
52 views

Work done on a battery

Consider a battery of EMF $E $ and label its positive terminal $P $ and Negative terminal $N $. Consider current flowing through the battery from $N $ to $P $. Then work is done by the battery. This ...
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1answer
81 views

Parallel voltage source concept

I am having doubt understanding this: If two voltage sources V1 and V2 are connected in parallel with different voltages like 2v and 3v is it possible or the scenario is wrong. An example is this ...
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0answers
17 views

Will a ZEBRA battery retain its charge when cooled down?

A ZEBRA battery needs a minimum temperature to operate. That is because only then the ions move freely enough. The electro-chemical reaction is as follows: $$NiCl_2 + 2Na \longrightarrow Ni + 2NaCl ...
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1answer
34 views

Alternator wear due to bad battery [closed]

I recently heard that a bad car battery (I assume "bad" means it drains faster than it was designed to) will wear out your alternator faster. How is this possible? Please note I am not looking for ...
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1answer
43 views

Energy stored in the battery of a circuit (single electron box)

Consider the following, a closed loop circuit with two different capacitors in series plus a battery that provides a voltage $V$ (in series with the capacitors). You may add a resistance if that helps....
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1answer
39 views

Determining potentials at points in a circuit with multiple batteries

I am asked to find the potential difference across the points $P$ and $Q$. Using Kirchoffs second law, I calculated the 'resultant' emf as being $E$. The p.d across each resistor would then be $\frac{...
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1answer
1k views

Short circuit in superposition

I'm really confused about the concept of short circuits. I don't understand, why when you short those two voltage sources, 20 and 10 ohm resistors become parallel? What happens with 4, 12, 15 ohm ...
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1answer
69 views

A second law of thermodynamics related question

In the center an empty (with air) not thermally isolated room with concrete walls, floor, and ceiling, there is hanging on a non thermally conducting thread a device ("conditioner"). The weather is ...
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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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1answer
79 views

Why doesn't the potential difference of a battery diminish when charge flows? [closed]

I want to know, when the charges travel from higher potential to lower potential of battery through the circuit then the potential difference must diminish. As it was previously made by keeping more ...
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3answers
162 views

Why the current doesn't flow in an open branch?

I know that the current will no flow towards the point A since there is no potential difference between A and the corresponding junction. However, between C and B, there is potential difference, so ...
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3answers
3k views

How is the electric field created by a battery inside a conducting wire constant?

My book says that a cell (or a battery) creates a constant electric field inside a conducting wire. They've made use of a cylindrical conductor for the purpose of explanation and said that since the ...
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2answers
130 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. ...
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2answers
30 views

New charge of a capacitor

How does the load of a charged capacitor vary when placing a dielectric between the plates while keeping the capacitor connected to the battery? If we have a capacitor that we have charged to the ...
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4answers
208 views

Inductor and Capacitor with a DC supply

Here is a LC circuit with a DC supply. When the switch is closed at t=0 capacitor behaves as a short circuit while the inductor behaves as an open circuit as the voltage across the inductor ...
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1answer
71 views

What happens when two identical real batteries are connected in parallel or in series?

I've been poking around looking for an answer for this, mostly because my intuitions have been wrong. What happens to the voltage and the resistance when 2 identical real batteries are connected in ...
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2answers
72 views

What is the cause of opposite electric current direction of flow of current inside a battery?

My question is that why the direction of current inside a battery is different than that of outside battery?Can someone explain how current is even carried inside a battery because free electrons aren'...
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1answer
29 views

Seperating Charges in a Cell

Sorry for not being detailed for my question here but how do charges seperate in a cell and when the electrons are pumped out of the battery does it return and become positive ? Yet again sorry if I ...
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2answers
2k views

Why does Li+ ion move to cathode in Li-ion battery?

When Li-ion battery is discharged or being used, the positive lithium (Li+) ions move from anode to cathode through the electrolyte. Meanwhile the electrons move in the same direction through the ...
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3answers
103 views

Power dissipated, different formulas, zero resitatance

Power dissipated on an electrical element can be given by: $$P = VI = I^2R = \frac{V^2}{R}.$$ When we have a battery with zero internal resistance, it means that the power it provides (or the power ...