Questions tagged [batteries]

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

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6
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1answer
129 views

Nernst Equation and Energy

I have a question regarding the Nernst equation and energy in a system. I know this is also a chemistry question, but I was interested in the thermodynamics (the energy of a system), so I decided to ...
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0answers
33 views

How to choose the method of circuit analysis?

I was just doing some revision, and I was wondering how to figure out which method to use for solving a given circuit? I tried using mesh analysis on the attached circuit but I got it completely wrong....
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1answer
50 views

Does Stopping Voltage actually produce 0 photocurrent?

The stopping voltage is the voltage applied across the photoelectric plates to measure the maximum KE of ejected electrons. This is as the electric field will apply a force against the velocity of the ...
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0answers
26 views

Question about amp-hour and batteries in series

I am a little confused about this wiring batteries in series and parallel and the effect of this on total time that these batteries can last(I suppose this is called amp-hour, correct me if I'm wrong) ...
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1answer
90 views

Different batteries in a parallel circuit

I have come across this question in my physics textbook. Two batteries are connected in parallel to a resistor (see the above image). The first battery generates $U1 = 9V$ of voltage and its internal ...
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3answers
92 views

RC circuit discharge while being connected to a battery?

I am facing a conceptual problem in analyzing the following situation which was part of a physics exam; A series RC circuit with $R = 200k \Omega$ and $C = 10 \mu F$ is connected to a 5V battery and ...
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2answers
118 views

What happens when a battery is dead?

While studying circuits I am having a question that when we say a battery is dead.Do we mean that the voltage difference between the ends has become zero?If no,then what actually happens?
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5answers
1k 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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3answers
76 views

Practical usage of batteries connected in parallel

Is there any practical usage in real devices for connecting batteries in parallel? Or is it more a theoretical construct? It seems to me that only batteries in series are used nowdays.
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3answers
71 views

Can anyone tell me why the answer to this question is D? [closed]

I think the current will go through earth wire but my physics teacher told us the current will continue to flow through the circuit.
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2answers
39 views

Empty and fresh battery in series

If you have 2 (e.g. 1.5V) batteries in series and one is dead/empty, what is the reason why a device is not working? Lack of voltage (1.5 + 0 is simply not enough for the device to operate)? From my ...
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2answers
56 views

Why did a 12V battery affect my motor more than two 9v batteries in series?

In class, we made a coil of wire and used it to make a simple electric motor with a magnet. I put two square 9v batteries in series for a total of 18v to power the motor. I then used a larger 12v ...
2
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1answer
82 views

Doubt while simulating electric circuits

Today, I was simulating DC electric circuits just for knowledge and fun using PhET interactive simulations. But I'm having trouble understanding these circuits which I made. I think that both these ...
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2answers
114 views

The importance and the role of a switch in an electrical circuit

There is this simple test: Three identical bulbs are connected in the circuit illustrated in the figure. When switch $S$ is closed: a] The brightness of $A$ and $B$ remains the same, while $C$ goes ...
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2answers
39 views

For a real battery, why is two identical bulbs in parrallel slightly more dim than just one in series

Image for reference: $$\begin{align} &r = 0.8\,\Omega\\ &\mathscr{E} = 1.5\,\mathrm V\\ &A = B = 6\,\Omega. \end{align}$$ The current when the switch is open, the only other resistor is ...
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1answer
46 views

Why do we subtract the voltage of the resistor from the emf voltage to find the terminal voltage?

I attached an image of a question from homework. I calculated the current in step 1) and then I calculated the voltage of the resistor. But why do I need to subtract that voltage from the emf voltage ...
-1
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1answer
30 views

Direct current electric circuit

Why when I reverse one of the three batteries in a torch light, the bulb does not light up? The three batteries (one of them is reversed) and the bulb suppose to form a closed loop. According to ...
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1answer
22 views

Question about electrochemical reaction in fuel cell

The electrochemical reaction on the anode side of a fuel cell can be expressed as hydrogen split into hydrogen protons and electrons. I'm doing some research about the electrochemical reaction in a ...
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2answers
44 views

Voltage when lamp burns out [closed]

In the question below, shouldn't the voltmeter read zero V because the circuit is broken and there is no current flowing? (the answer in the text is 12v)
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3answers
107 views

Why doesn't the flow electrons occur in a broken circuit?

Take a battery and connect a small led bulb across it with the help of two wires. The bulb will glow, but if I cut a small piece of wire from any part of the connecting wires,the circuit will not work ...
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1answer
50 views

Intuition behind swapping the known and unknown resistance in a slide wire meter bridge

Today I was learning about wheatstones and balanced meter bridges. But while learning about the sources of error while working with the meter bridge (measuring unknown resistance), I couldn't ...
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2answers
161 views

How do voltmeters measure work done over a component?

In my physics class, we were shown the picture below to measure the current and potential difference through a component. We were told that the resistance of the ammeter is as low as possible, and the ...
3
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1answer
1k views

Why would 4 batteries in a device not drain equally? [closed]

I noticed a motion sensor light was weak so I assumed the batteries were dying and removed them. To make sure I was right, I tested the 4 D alkaline batteries. One was completely dead. One was on the ...
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2answers
52 views

Power in a simple electrical circuit [closed]

In this picture, as we know power due to heating of the resistance is $V^2/R$ . Now, if we add a parallel resistance to the circuit, the power dissipated through this resistor is also $V^2/R$ ...
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6answers
2k views

Does the resistance of the voltmeter affect the behavior of this circuit?

I have this setup. It consists of a battery of no internal resistance with voltage $V$ and a resistor with resistance $R$. It also consists of a voltmeter of some (not so large) resistance as good ...
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1answer
173 views

Li-ion Battery charging

Why are constant current mode and constant voltage mode needed when charging Li-ion batteries? Why do we apply saturation charge even after the cell voltage reaches 4.2V? What exactly is 'I-sense' in ...
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2answers
67 views

Voltmeter connection across motor

I want to measure the voltage(potential difference) acorss the motor A. Where should I connect the voltmeter? I am confused between two possibilities: between X and Y (between two ends of the motor ...
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1answer
24 views

Uncertainty estimation of a quantity after its calibration

I have to calibrate power output of a diode to its input voltage. The voltage source has negligible error but the power meter has significant uncertainty (a couple %). I take a number of power ...
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5answers
125 views

Potential Difference of a battery - What does it mean?

I have studied current electricity for a while now. When I look back at basic concepts, I am quite clear about what current, electron, resistance is. But I cannot imagine about the potential ...
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3answers
813 views

Hardest circuit diagram [closed]

I have provided an example of the type of problem I am having issues with. In the given diagram, the resistances and batteries are identical and the batteries do not have internal resistances(for the ...
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0answers
26 views

Electronegative - Electropositive atoms can attract ions?

Well I was just wondering how a copper-zinc battery works, with electrolyte an equilibrium of water and NaOH. It says that NaOH is dissolved (I understand that) into water forming H$_4$O$_8$Na+ ions ...
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2answers
57 views

Is (DC/battery) voltage a result of charge? or energy? or both?

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 ...
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4answers
128 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 ...
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3answers
8k views

How can you calculate (or convert) the Wh of a capacitor whose energy is given in Farads

When trying to compare the energy in a battery to the energy in a capacitor, the units don't match up. How can one compare a battery whose Ah are 10 and Voltage is 3 (for a total of 30 Wh) to a ...
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1answer
42 views

What is difference between current and voltage? [closed]

If current passes through the bulb not using it up then how battery becomes weak after sometime?
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3answers
87 views

Electrons and wires [duplicate]

The electrons that carry the electric energy are in wires or in the battery ? battery provides a potential difference but from where electrons flow to make for example a bulb light. If they flow from ...
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1answer
61 views

Misconception about flow of charges

Let's say I have a 5V battery connected in the manner shown in the diagram. I've tried this setup with all sorts of things like pouring brine(salt water) into the soil to decrease its resistance so ...
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4answers
11k views

Can single DC 1.5V battery generate 1500 watts of power?

Suppose there is a DC $1.5\mathrm{V}$ battery connected with $1.5\times10^{-3}\mathrm{\Omega}$ resistor. Then the amount of circuit current is $I=V/R=10^3\mathrm{A}$. (according to Ohm's law) I know ...
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2answers
81 views

$V = 4 volts$ but $I = 0$

Recently in my school, I tried to generate electricity from plants in a flower pot with copper and Zinc electrodes. The Potential difference in the voltmeter read 2 to 3 volts but when I connected the ...
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1answer
179 views

Question about circuit with two cells [closed]

Edited - could someone explain how you treat a circuit with two cells in respect to circuit laws and also whether the section in the middle is in parallel or in series. Second Edit: I’ve researched ...
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2answers
65 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 ...
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4answers
147 views

How is energy conserved in a theoretical circuit where you put a lightbulb and two rechargeable batteries like… (diagram included)

In the beginning the first battery is fully charged, and the second is fully discharged. As the circuit is connected the discharging battery recharges a dead second battery and light is emitted from ...
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2answers
48 views

What possible advantage could there be in connecting several identical batteries in parallel? [duplicate]

In two-cell flash light,the batteries are usually connected in series. Why not connect them in parallel?
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0answers
42 views

What force is responsible for the movement of electrons in a current caused by an electrochemical source?

From what I have read, batteries provide an electrochemical potential that causes electrons to move from the negative terminal through a conductor to the positive terminal. I have read numerous ...
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2answers
1k views

Physics of batteries (volts vs charge)

Car batteries are usually 12 V. What is the difference between buying a car battery and hooking up a bunch of cheap household batteries in series? Both would register at 12 V. I assume that cars need ...
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1answer
28 views

Hydrogen oxygen fuel cells

In hydrogen - oxygen fuel cell, the electrode used is carbon electrode.Hydrogen is passed through through the anode compartment where it is oxidised. Oxygen is passed through the cathode compartment ...
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1answer
42 views

How a battery maintains the current in the circuit? [duplicate]

How a battery maintains the current in the citcuit? Iwant to know each and every step of this process mathematically and theoretically also.
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1answer
35 views

Confusion about calculating resistances & terminal voltage

I'm looking at an exercise where a battery is powering two parallel light bulbs. Given are the battery's EMF ($12.0 V$) and its terminal voltage in this particular circuit ($11.8 V$), as well as the ...
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1answer
66 views

Using a significantly large metallic sphere, could we draw out the electrons from the negative terminal of a battery?

I've pored over many articles on electrochemical cells, and I understand that on the oxidation side of a zinc-copper Daniell cell, the anode is highly negatively charged because zinc participates in ...
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1answer
33 views

How are batteries affected on planes? [closed]

I'm currently an engineer and was fascinated at how technology came to be and how we were able to find out that we can take energy and essentially store it for a later time. I was thinking about ...