Questions tagged [batteries]

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

Filter by
Sorted by
Tagged with
2
votes
5answers
319 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, ...
1
vote
1answer
69 views

Why does all the voltage has to be dropped in a circuit?

In a simple circuit with a single resistor the entire voltage provided by the cell drops. It is independent of the resistance. Why does this happen? What is the mechanism behind this? I mean why does ...
3
votes
1answer
179 views

How the current moves in the battery and outside the battery?

Does it move again to the negative terminal or stays at the positive terminal until the electrons all come .so the voltage will.be zero and current flow .I want simple clear explanation because i am ...
0
votes
2answers
430 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 ...
1
vote
0answers
163 views

Quartz piezoelectric battery

I'm designing a battery that uses quartz crystals to hold/produce a current for a long time using piezoelectricity. My question is: Would it be more efficient to have multiple small quartz crystals ...
2
votes
1answer
152 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 ...
0
votes
1answer
2k views

Connecting cells in series and parallel

When 2 cells is connected in series of the same emf like the following: [just the part of the circuit that I need...] The resultant emf will be twice as the previous identical emf. If we reverse ...
1
vote
0answers
54 views

Is this Thevinin equivalent of a voltage divider, correct?

Found the PDF version of The Art of Electronics (Horowitz and Hill) recently, and, having nothing better to do... I thought I'd give it a read. It wasn't long before I hit a wall (courtesy: my inept ...
1
vote
1answer
409 views

Why does battery generate less terminal voltage difference when current flows?

The terminal voltage difference of a battery means the difference of voltage between the two termials of a battery. Now, a battery has a voltage at the positive terminal and a voltage at the negative ...
0
votes
3answers
2k views

Backwards proof for balanced Wheatstone bridge

We know that in this Wheatstone bridge if, $\bf{I_3 = 0}$, it can be derived that $\bf{\frac{R_1}{R_5}=\frac{R_2}{R_4}}$ . But could we prove it backwards, mathematicaly, that - if in such a circuit $...
0
votes
1answer
2k 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 ...
2
votes
1answer
298 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 ...
15
votes
3answers
4k views

Does current run forever in water? (assuming the supply voltage is there forever)

Suppose pH of water is $6$, I think this means there is one $\text{H}^{+}$ ion for every $10^6$ water molecules. When we plug in the battery, I believe we see a current as the $\text{H}^{+}$ ions ...
1
vote
2answers
40 views

How is the loop law applicable when I connect a battery with an ideal copper wire?

We would have a potential rise but where is potential drop? Considering wire to be having negligible resistance.
1
vote
1answer
1k views

Electromotive force of a battery

The definitions of electromotive force of a cell that i have read include: 1.When no current is drawn from a cell,i.e., when the cell is in open circuit, then potential difference between the ...
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 ...
1
vote
2answers
139 views

Why do batteries in series add up in voltage? (real explanation requested)

This has been asked before but I need to be clear on what kind of answer I'm looking for. All the other posts are just water analogies. I get it, you add the voltages together. And there's a magical ...
0
votes
1answer
204 views

Not understanding inductor behaviour in RL circuit

This figure from Halliday's book is perfect to go with my question. I've been trying to understand how exactly indutance works almost the entire morning, I think I need another perspective, please. ...
0
votes
2answers
254 views

Resistance in internal battery, voltage source

I was reading the post Which dissipates more power, a small or big resistor? and DanielSank's reply said Now, any circuit you would reasonably call a "voltage source" must have a low internal ...
2
votes
2answers
456 views

Diode IV experiment

Ive been looking at experiments to look at the IV relationship for a LED, but I see most of them use a rheostat instead of a series variable resistor and my question is, what is the advantage of using ...
1
vote
0answers
52 views

Issues reading a paper about batteries

I am looking for answers regarding a paper I am reading right now. I either found stupidly high values or strange SI unit. This paper is about battery charging, and the battery model used brings me ...
1
vote
4answers
4k 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 ...
-3
votes
1answer
753 views

Can a mobile phone emit gamma rays? [closed]

I heard that inside the battery of mobile phones (but also of other electronic devices) can happen quantum leaps that cause the emission of gamma rays photons. Is this phenomenon really possible?
0
votes
1answer
84 views

Circuits in parallel of different voltages

I've been having difficulty in understanding why the voltage across the resistor $3$ is $10V$. My main problem is understanding why the $12V$ resistor couldnt for example drop $1V$ on the first ...
0
votes
2answers
936 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 ...
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 ...
0
votes
2answers
36k 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 $E=\frac{...
2
votes
2answers
644 views

Circuit with three capacitors and a switch [closed]

I have a homework problem where I have a battery connected to a capacitor and a switch that connects the capacitor to 2 others in series/disconnects the circuit from the battery. The question is: ...
-1
votes
1answer
520 views

Why is the voltage in my battery rising?

While playing with some 9 volt batteries in a series circuit, I noticed that the voltage of the battery as measured by my voltmeter was increasing at a constant rate. After placing a bulb in my ...
1
vote
2answers
83 views

Current in circuits and conductivity

I'm really puzzled with a problem for a rather long time and I can't really seem to be able to solve it at all. It has to do with the electrons that move in a circuit. We know that a battery builds ...
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 ...
0
votes
3answers
1k views

Voltmeter- Readings

What would the reading be on this voltmeter? Suppose The battery is $5V$. Would the reading be $5V$? If you see it from the other way, the two ends of the voltmeter are connected by ideal wires; ...
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 ...
0
votes
3answers
403 views

Does a higher e.m.f give a larger current?

I was told that e.m.f. is the work done on the charge carriers (i.e. electrons in wires or free ions in electrolytes). Does this mean that e.m.f is preportional to current (the rate of flow of charge)...
0
votes
1answer
230 views

If a resistance of $0$ ohms and $x$ ohms are in parallel does all current pass through the $0$ resistance? [closed]

If a resistance of $0 \Omega$ and $x$ (and $x>0$) are in parallel does all current pass through the $0$ resistance? For instance in the following circuit: Set variable resistor to o ...
2
votes
3answers
1k views

How does connecting batteries in series work?

My question may seem naive so please bear with me. I just began learning about circuits and I am having problem seeing how two or more batteries can be connected in series and how the current flows in ...
0
votes
1answer
73 views

Charge generated by battery or wires?

According to emf concept,we say that due to potential difference between electrodes of battery, electrons or charges want to move to opposite electrode. But electrodes are not joined. So they have to ...
17
votes
2answers
3k views

Increase in mass of battery of my smartphone [closed]

The charge on my smartphone was zero. I charged my phone to its maximum capacity. How much mass $\Delta m$ did my mobile gained after charging the battery? Maximum capacity of the smartphone's ...
0
votes
1answer
118 views

Current relationship with different light bulbs

I have a circuit in where there are 3 different bulbs (circular, oval, and rectangular, the circular is the dimmest, the rectangular is more brighter, and the oval is the brightest. Now , I am ...
0
votes
2answers
3k views

Working of a potentiometer

Why do we achieve a zero deflection situation in the galvanometer when we slide the jockey on the potentiometer wire ? Or what is happening in the secondary circuit that causes zero deflection in ...
0
votes
3answers
184 views

Parallel combination of batteries [closed]

What is the current through resistance of 6 ohm in the figure. please explain through Kirchoff laws and keep it simple on college level
2
votes
1answer
101 views

Does this kind of circuit work?

I am going to see if having electric voltage through fruit will slow the decay. So I have my treatment set up here: and I am going to wrap this so that: However, my teacher told me that this might ...
1
vote
1answer
132 views

No-answers-found Li-Ion battery questions [closed]

Background I've spent almost 7 hours researching about Li-ion batteries because my Galaxy S2 only lasts 2 hours with all turned off and only 40 apps installed (removed system apps and bloatware) and ...
2
votes
3answers
1k views

Why is the potential drop zero across a wire of zero resistance? [duplicate]

Okay, even if the wire has zero resistance, then charges are being transferred in the direction of electric field, which means there must be a potential drop according to the distance travelled by the ...
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) ...
0
votes
1answer
273 views

Simple circuit with mesh current. Two resistors, two batteries [closed]

I can't find current through 6k resistor using mesh-current method. Using KVL on left and right side you get: \begin{align} V_\text{4k} + V_{6k} - 10V =& 0 \tag{left loop}\\ 13V \text{(voltage ...
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 ...
1
vote
3answers
3k views

What is the volume of gases liberated when a battery is charged?

Apparently Hydrogen/Oxygen are liberated when a Lead-acid battery is charged. If true, how does one calculate the expected volume & rate at which each gas is liberated when a battery is charged?
1
vote
1answer
272 views

Why is the work done by a battery associated to a potential energy even if the processes are not reversible/conservative?

Consider an isolated capacitor (no battery). Since the electrostatic force is conservative, the infinitesimal work done on the capacitor plates can be written as $$\mathrm{d} W=-\mathrm{d} U_e $$ ...
0
votes
1answer
40 views

Why is Alternative energy most commonly stored in metal acid batteries? [closed]

Why is alternative energy most commonly stored in relatively expensive metal acid batteries, which have a short life, rather than hydrogen gas accumulated through electrolysis? Hydrogen is a ...