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

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3answers
232 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 ...
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1answer
24 views

Is a real voltaic cell always schematically equivalent to an ideal battery and a resistor?

In the diagram I have attached, the top circuit is the schematic equivalent I am trying to use to model the middle circuit which uses real voltaic cells (that have internal resistance). I am not sure ...
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1answer
29 views

E. M. F and potential difference [closed]

Here i =emf/R+r -(eqn.1) . Pd across the cell is equal to potential drop across resistence R. i. e pd =iR . Pd = (emf x R)/R+r -(using eqn. 1) . Also pd =emf -ir . emf -ir =(emf x R)/R+r . Hence ...
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1answer
27 views

Is the $C$ rating of a battery a measure of Capicitance or Charge?

I have become confused as to the meaning of what a C rating of a battery means. My understanding is that because a C rating is measured in milli-ampere hours the units should cancel to be a unit of ...
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3answers
35 views

EMF or terminal voltage?

I have a doubt that is: What does this statement mean: "a 6 V battery". Does this mean that the EMF of the battery is 6 V or the terminal voltage of the battery is 6 V? If the battery has internal ...
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2answers
4k views

Calculating the energy supplied by a battery

If you wanted to calculate the energy supplied by a battery in time $t$ you would use $E=VIt$ where $I$ is the current through the battery. If the internal resistance is $r$ we could also use ...
4
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2answers
187 views

Will the two capacitors be charged in this circuit?

Is such a circuit possible to exist with the two capacitors charging? Because if we considered the outer loop using Kirchhoff's law we get: ℰ = q1/C1 + q2/C2 But since the two capacitors are ...
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1answer
107 views

Why does a battery die more quickly when more resistors are added to the circuit?

I will be explaining what I think: A battery acts like a pump which provides energy to do work on negative charges to move them towards the negative terminal, and hence creating an electric field. ...
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2answers
482 views

Why the EMF of a battery doesn't depend on distance between the two electrodes?

I have read that resistance of a conductor is directly proportional to its length. So, the EMF of a conductor (electrolyte of battery) should increase with increase in length/distance between the ...
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1answer
26 views

If a battery is open on one end but connected on the other, does it raise the potential on the connected end?

If a battery has one end open and other end connected to a circuit will the battery increase the potential at the point of connection?
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1answer
29 views

What is the work done by battery and what does work done on battery mean?

Suppose we have a charged capacitor connected to a battery. Now we push the plates of the capacitor away from each other decreasing capacitance and hence energy stored in the capacitor decreases. Now ...
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5answers
95 views

Brightness of 2 Lightbulbs hooked up to Capacitor [closed]

The figure shows a circuit consisting of a battery, a switch, two identical lightbulbs, and a capacitor that is initially uncharged. a. Immediately after the switch is closed, are either or both ...
2
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1answer
78 views

What do the batteries actually do to the electrons?

I am plagued by this simple question that what force exactly causes the motion of an electron in the middle of a lattice of electrons of a wire? a. Is it an electric field created inside a wire due to ...
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1answer
21 views

On a AC to DC adapter there are +12v wire with 24A and -12v have 0.5A. How many amp this adapter will provide in total? [closed]

I have a PSU of a pc which is 500w. I want to charge a 12v 100ah battery which need 20 amp of current. Is this psu can provide current that I have wanted? Main question is On a AC to DC adapter ...
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1answer
31 views

Charging of a battery

A battery has an Emf 6 Volts. It is completely discharged. It is charged by maintaining a potential difference of 9 Volts across it. If the internal resistance of the discharged battery is 10 ohms, ...
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2answers
654 views

If I charge a battery using a much higher current, can it explode?

If I have a 12V 4Ah lead acid battery and use a battery charger that, let's say for example, can charge 10A, 50A, or 100A. If I theoretically turned it to 100A will the battery explode? I understand ...
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1answer
53 views

What happens in the RC circuit when being charged?

Say I have this RC circuit and at the start, the switch is off (current going from left to right and the starting point is just above the battery). I understand that then the capacitor acts just ...
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4answers
85 views

Electrons moving in a simple circuit with a battery and a light bulb

I believe my understanding of electric currents is flawed and want some help to clear up a few things. I'm not looking for a precise scientific understanding, but to understand the basics. I'll try to ...
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1answer
35 views

Adding two same DC voltage source in parallel

In a parallel circuit(imagine two branches),with one DC voltage in a branch and another DC voltage in a branch, what is the method of computing the total DC voltage? The voltage through each component ...
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3answers
152 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 ...
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3answers
656 views

Why is there electric field OUTSIDE a battery?

Correct me if I'm wrong, but a battery's electric field is like an electric field of a capacitor consisting of two parallel plates. But we know that the electric field outside the two plates is zero. ...
5
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1answer
112 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 ...
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4answers
331 views

How can there be a voltage when there is no current?

I'm told at school that the Electromotive Force (e.m.f) of a battery equals the potential difference between the terminals of the battery when there is no current. How is that possible? How can there ...
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2answers
235 views

How electrical energy is transfered trhough a wire, and what's flow of charge?

I've read these texts about misconceptions about electricity. This is my understanding: Electrons do move, mut slowly and randomly. What happens is that, in fact, they're just 'conducting' the ...
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1answer
40 views

How does a capacitor get charged while the charger circuit isn't closed? [closed]

a capacitor is a very known device in circuits that can be used as a short-time battery by charging it using another source, but how does it really get charged? if the plates of the capacitor don't ...
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1answer
57 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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3answers
12k views

Why connect cells in parallel?

Say there is a circuit with two 1.5V cells, and a 100 ohm resistor. If you connect two cells in series, then the total emf is 3V. And the current will be 3/100 = 0.03 A. (Using V = IR): If you have ...
3
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1answer
37 views

Does the internal resistance of a battery dissipate heat as expected?

A common real battery is often modelled (to a good approximation) as a perfect voltage source having emf $\varepsilon$ with a series internal resistance $r$. So, when a current $I$ is drained from it, ...
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0answers
16 views

How to calculate ion lithium battery voltage?

I have raw data from cyclic voltammetry test of ion-lithium battery. But I need nominal voltage or Open Circuit Voltge (OCV), like is reported in the literature. But I only have Voltage (V) vs ...
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2answers
2k views

How many grams of explosive are equivalent to the energy in a battery?

In the movie Terminator 3: Rise of the Machines, Arnie's fuel cells were twice shown to be extremely devastating when their stored energy was released. In real life, how many grams of, say, gunpowder ...
2
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4answers
6k 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 ...
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4answers
101 views

Voltage of a battery in a circuit with an infinite resistance [closed]

I have a dilemma that I would like to share with you concerning batteries (without neglecting internal resistance), emf and resistance of a circuit. To better visualize my question you may need to ...
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1answer
34 views

Estimate battery's real capacity in real time [duplicate]

The maximum capacity of a battery during usage can vary from manufacturer's specifications due to factors like temperatures and battery health. Because of that i want to estimate the real maximum ...
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0answers
43 views

What is the status of energy storing battery technology? [closed]

Most of electronic devices work off electric mains for short time (e.g., on smart phones - for a day or less). It is disappointing the solid state battery technology is moving slowly while othe ...
3
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0answers
37 views

What determines the speed of charging of a battery? [closed]

Recently we have seen the surge of superfast mobile phone charging. Just an example: http://www.bbc.com/news/technology-30708945 What underlying physical principle determines the speed of charging of ...
2
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0answers
28 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 ...
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1answer
201 views

Battery charging using a windmill?

i want to charge 4*(12V/100AH battery) using a 3*( 12V/5AMP GENERATOR ) which is drawing its power from a windmill. these battery have to heat 500 litre of water from 30 celcius to 50 celcius how ...
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1answer
79 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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0answers
11 views

What is the distribution of a battery transmission?

I have an energy-harvesting battery attached to a node, transmitting data over Rayleigh flat fading channels. Energy in the battery is used, and simultaneously energy is harvested and stored. I want ...
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0answers
62 views

Internal resistance of a battery

It is my understanding that internal resistance of the battery is mainly due to resistance of its electrodes and electrolytes. During the charge or discharge of the battery, there's a potential drop ...
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2answers
106 views

Battery and charge separation

In this question : What is the difference between a battery and a charged capacitor? http://physics.stackexchange.com/q/32394 It is said that the battery does not have a charge separation on its ...
3
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5answers
295 views

Why does not a battery kept in empty space discharge on its own? If space between the terminals is empty, what prevents the electrons to flow?

Given here is the picture of a twisted battery kept in free space (vacuum). Will the battery discharge quickly? I mean, it should discharge faster than it would if we were to connect the terminals ...
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0answers
23 views

Setting up current directions in multiloop circuits with more than one battery

I'm currently working on this problem: I must find the current in each battery. I have certain doubts when estipulating the currents: How many $i$ exists in this problem? The current going in a ...
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1answer
53 views

Deriving Loop Equations in a Circuit with 2 batteries?

First time posting here, so please help with formatting. I need help deriving loop equations for this becaue the 2 batteries/power supplies are throwing me off. https://i.imgur.com/MJH6mIM.jpg The ...
2
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1answer
83 views

Given a large, multiloop circuit with resistors and batteries and I'm not sure how to simplify it. (When NOT to combine resistors?) [closed]

So here's the circuit, and the question is looking for current i: All resistors are 2 ohms and the batteries are 5 volts. I'm trying to apply the resistance combination Kurchov rules to make this ...
6
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3answers
9k views

What happens if I throw a battery into water?

Today I have by accident thrown a AAA battery into a bucket of water. I fished it out of the water immediately (within 20 seconds or so) and nothing notable had happened and the battery is still full ...
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1answer
899 views

How can a fruit be used as a battery cell?

Fresh fruits can be used as batteries for glowing bulbs, but how this is possible? I mean how can electric charges flow through fruits? Do they contain chemicals like cells?
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1answer
68 views

Why magnesium is less reactive than lithium

Why divalent magnesium is less reactive than monovalent lithium? Intuitively second group elements should have lower ionization energy than first group but we observe opposite. For example magnesium ...