# Questions tagged [batteries]

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

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64 views

### Electric field of battery

What happen when a charge particle is kept between the two electrodes of battery ? Will the electric field between those two electrode affect that charged particle? 81 views

### Fully charged capacitor is connected to another battery

Suppose an empty capacitor with a capacitance A Farad is connected to a B voltage battery. After the capacitor is fully charged, ...
45 views

### Why does taking one current from any cell work?

$\text{We were doing problems on Kirchoff's Laws in my class. The problem :}$ My Professor told that from $B_1$ current $i_1$ is flowing which splits into $i_2,i_3⇒i_1=i_2+i_3$. Then he used Kirchoff'...
38 views

### Confusion on Voltage across a battery

If I have a battery that is 0.1m in length, with the positive and negative terminals situated at the top and bottom, and I am trying to calculate the voltage (electric potential difference, Vdelta = ...
59 views

### Can potential at the terminal of a resistor directly connected to negative terminal be non zero?

what will be the potential difference between point a and b? I have been trying to solve this problem for a long time but couldn't. It has been suggested to solve this problem considering the ...
499 views

### Resistance-capacitance (RC) circuit

My textbook says: "This continues until the voltage across the capacitor matches the emf of the battery" If I were to have a resistor in series with a capacitor, would the voltage across the ...
58 views

### Grounding in Circuits [closed]

The question is to find the current through the 8 Ω resistor. My textbook says that it is 3A as there is 0 potential at points "a" and "b" and thus it must drop by 24 V across the ...
2k views

### Why is there an electric field around this closed electric circuit?

I have difficulty understanding the picture below. I can understand the green magnetic fields. But why is there an outside, red, electric field? Isn't the electric field guided entirely through the ...
75 views

### Understanding voltage as a relative measure between two bodies

Voltage, electric potential difference, electric pressure or electric tension is the difference in electric potential between two points, which (in a static electric field) is defined as the work ...
106 views

### Potential difference in circuit of dry cell [duplicate]

I referred to this question potential difference but had a few doubts as to why do electrons move in a circuit? What exactly causes them to do so? And what is the chemical reaction in the cell which ...
1k views

### Is every finite circuit "solvable" using Ohm's law and Kirchhoff's loop rules? [duplicate]

Whenever I have solved circuits (only cells, resistors and wires), it has only been necessary to use Ohm's law (or things derived from Ohm's law, such as how two resistors $R_1$ and $R_2$ have ...
478 views

### Why is the current equal when the resistors are in series? [duplicate]

I am a High schooler. And I learned that the current is always the same when the resisters are in series. I was told about the water analogy. If the first one had had a smaller resistance wouldn't it ...
53 views

### What is a cathode and an anode in general sense

i am totally confused and not able to understand the difference between cathode and anode Cathode is defined as reduction point but why is its sign -ve in a terminal and different in a battery Anode ...
84 views

1 vote
61 views

### Time-reversal in a simple current loop

In classical physics, time and velocity change sign under time-reversal while position, acceleration and force do not. An accelerating particle going to the right becomes a decelerating particle going ...
214 views

### Equivalent EMF of unequal cells connected in parallel

I'm aware of the formula to calculate equivalent EMFs of 2 cells connected in parallel as shown in the top figure. But what happens if we switch the polarity of one of the cells? Shouldn't the ...
359 views

### How does current get reduced in resistor?

How does the resistor reduce the current? I know that when there is no resistor in the circuit the current is higher than the current when there is a resistor. But, my question is: How the resistor ...
1 vote
78 views

### Does charged Li-on battery burn more than discharged one if damaged? [closed]

I am wandering if a charged Li-on battery burns more than discharged one if damaged, considering that the charged one has more energy in it. Thanks.
1 vote
139 views

### Confusion In Fundamental Properties Of A Battery

Ever since I started reading about electrostatics and current electricity I have gotten ever so confused by various things. After watching video lectures by several different people and reading ...
1 vote
50 views

### How long does a headphone last on a given battery? [closed]

Sennheiser HD 598 has 50Ω impedance. It has a 3.6mm cable, but I am planning to do a simple DIY project to replace the cable with a bluetooth receiver, a 3.7V 1000mAh battery (and a charging board). ...
1 vote
59 views

### Can I apply Kirchhoff's current law to two separate nodes which are connected only by an ideal wire? [closed]

Suppose there are 2 nodes A and B in the above circuit. If A has 2 incoming currents $I_1$, $I_2$, and B has 1 incoming currents $I_3$, $I_4$, is it correct to write the equation of whole nodes and ...
1 vote
59 views

### Circuit problem [closed]

Hello, can someone please help me on this problem? Question: calculate the potentials at A and B. The solution says that they are both 12V "due to symmetry" but I have no idea what is the ...
2k views

### Why is the current entering a conductor the same as the one exiting it?

Suppose I have a conductor connected to a battery. The current starts flowing through the conductor. Why is the current entering the conductor the same as the current leaving the conductor? Its ...
3k views

### How is the answer to this question $1/c$ seconds?

This is a question from the YouTube science content channel Veritasium. The below image shows the question. The question is about when will the bulb begin to glow after the switch is turned on. The ...
56 views

### How long does it take for a battery to begin to produce a current after it is shorted? [duplicate]

From the moment you short a battery, how long before the current BEGINS to flow. Does a virtual photon need to travel the path of the wire? I was thinking it would be the length of the wire divided by ...
921 views

### A loop of wire with circumference of a lightyear is connecting a bulb and a battery. How long will the bulb take to light up?

Imagine a circular loop of conducting non wire with a perimeter of a light year. There is a powerful battery (able to produce a voltage that is higher than the drop in wire resistance) and a bulb ...
54 views

### Asking for proof for total voltage is equal to the sum of the voltages of the resistors (connected at series pattern) [closed]

Recently I was taught that when a set of resistors are connected as a series pattern the total voltage of the resistors is equal to the sum of the voltages of each resistor. I know how to prove this ...
663 views

### Why the Voltage across a capacitor equals that of the battery

This is how I look at capacitors. When the battery is connected electrons are pushed from the battery and accumulate on the capacitor, this occurs until the repulsive electric force equal that of the ...
144 views

### Inductor back emf

If I have that circuit, the equation that describe the circuit is: $\epsilon = L \frac{dI}{dt}$. Now, if the back e.m.f. is equal to the source e.m.f, how current can pass? and it should pass because ...
57 views

### Physical laws limiting the size and energy density of battery/capacitor [closed]

The size and energy/power density of battery are always under active research and it would be nice to have small-sized battery with high energy density as well, but this seems to be nearly impossible. ...
168 views

### What is the relation between electromotive force and energy stored in a cell which can be converted to other energy in the external circuit?

We usually define electromotive force of a cell as the energy stored in the cell(atleast I have noticed it to be defined like that). But isn't electromotive force equivalent to electric potential ...
1 vote
177 views

### Why is voltage used when measuring the strength of a battery and not electric field?

I'm not sure how to ask this but, I started learning about electromagnetism with how charged particles behave in electric fields. This was easy and intuitive to understand. But I felt a disconnect ...
2k views

### Why does a drop in resistance lead to a drop in voltage?

I was working on this question which I know the answer to but I am still confused. I get that resistance is due to collisions on the atomic scale where the electrons' kinetic energy is transferred to ...
55 views

### Will the electron in a circuit without a load gain ever more potential energy every time it passes through a battery?

Say we have a circuit without any load, just a wire and a 1.5 V battery, so there is no full potential drop as it gets to opposite terminal. Will there be 1.5 V of potential added every time it passes ...
170 views

### British Physics Olympiad Round 1 2010 Q2a - Find potential difference between A and B [closed]

I've been trying some British Physics Olympiad past papers. In the 2010 Section 2 paper, the first question is the following: I've never seen a circuit like this, and I'm unsure what the correct ...