# All Questions

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71 questions
40 views

### Electric Potential in the Center of a Electric Dipole

I thought the electric potential at point B would be positive because placing a positive charge at point B would cause it to move releasing energy while doing so. The answer key states that the ...
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### Why does a voltaic cell induce an electric force proportional to voltage?

I'm trying to understand the intuition behind Ohm's law (that current is proportional to voltage). I understand the basics of the Drude model: if the electrons frequently collide and on average reset ...
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### What do we mean by positive terminal and negative terminal?

What do we mean by positive terminal and negative terminal of battery ? What is the electric potential of both positive terminal and negative terminal ? Does positive terminal mean positive electric ...
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### Why does the potential along a uniform current-carrying wire vary with the distance along it?

Is it because as the electrons move further through the wire they lose more energy due to resistance? Also, in this context, I believe potential refers to the electric potential energy but I am unsure,...
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### Summing up very basic terms in basic electricity [closed]

My attempt to define following terms as per my understanding. I am currently at high school. Electromotive force (EMF): Potential between two terminals when open circuited. Wikipedia's ...
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### Can electric potential be discontinuous?

I am studying the following problem, which is 9.11 of "Modern Electrodynamics" by Zangwill. The idea is that you have a wire attached to a perfectly conducting sphere (radius $a$) buried into the ...
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### Potential difference in a nonuniform electric field

Let's say I have two points in a nonuniform electric field and those points have the electric potential 10 V and 5 V. If I then would use a voltmeter to determine the voltage between those points ...
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### Electric potential at ONE point around an infinite line charge

The problem states that you've got two infinite charged wires with linear densities of charge (l and -l) and you must calculate the electric potential at any given point. I dont know how to do this ...
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### Question about Work performed between two points within an electric field

In an exercise in my Physics Textbook, I was asked to calculate the amount of Work necessary to move a charge of -$1.6\cdot10^{-6}$ Coulomb from P to R, and from R to O (see attached picture below). ...
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### Why do we use electrical potential difference in a circuit instead of electrical potential energy?

When talking about a circuit, why does voltage stand for electrical potential difference equal to $\frac {Work}{q}$ when instead we can use electrical potential energy? Is it because the charge of an ...
285 views

### Variation of induced electric field with distance

Let's say we have a cylindrical uniform magnetic field which is varying with time at a constant rate. As the distance from axis increases, induced electric field or electromotive force (EMF) varies as ...
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### EMF developed in a varying magnetic field

Let's say there's a cylindrical varying magnetic field (varying at a constant rate) and I have a conducting body, let's say a rod placed in a plane perpendicular to magnetic field. I am having a ...
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### What physically determines what voltage something has? [closed]

I know that voltage is energy per charge / energy per electron, but since something such as a wall outlet has 120V with a lot of current but a mostly harmless low current Van De Graff generator has ...
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### How to simplify such structures to calculate equivalent capacitance?

I am self studying electrostatics for competetive examinations but there is this series of questions demanding equivalent capacitance and I direly need a intuitive understanding of these situations.
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### Voltage/Charge in a Negatively Charged Balloon

Could somebody explain the following excerpt from my Physics book? I don’t understand how, if the voltage of the balloon is so high, the charge can be so low? Maybe it’s just worded confusingly: “...
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### Same Charge or Same Potential?

I was studying about sharing of charge between two charged conductors when I came across this statement - When two conductors are joined together through a conducting wire, charge begins to flow ...
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### How to simply explain potential?

Could someone explain what potential really is? I have read about it in many books and on many sites but no one really explains what it represents and how it really works? I know the formulas about it,...
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### Electric potential of uniformly charged wire

I want to calculate the electric potential of a uniformly charged wire with infinite length. The problem I run into is that one boundary of the integral is $\infty$. That’s what I have so far: Given ...
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### electric potentials of charged concentric shells after earthing [closed]

Two concentric shells have radii $R$ and $2R$, charge $q_1$ and $q_2$, and potentials $3V$ and $V$, respectively. Now, the outer shell is earthed. What will their final potentials be? I have always ...
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### How is PD = EMF for an open circuit?

For an open circuit, $V = E - Ir$. People say since there is no current flowing, $V$ is equal to $E$. However $V = IR$, where $R$ is the external resistance, that doesn't exist either so how can ...
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### Why is potential difference in ECG considered a vector?

In the electrocardiogram, there are leads placed on the limbs and an "electrical vector" is calculated as the difference in potentials measured I the two leads. The direction is given by the line ...
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### Can conductor be charged?

I have a copper conductor. For a while, I apply a voltage of $12kV$ DC from a source. After removing the source, will the conductor stay charged from the source if is not earthed? Will it discharge ...
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### Ohm's law for stones

Suppose I drop stones from a height. Now, we define quantity analogous to electric current called mass current. Now, to get an analogue to Ohm's law, we need drift velocity for stones. For electrons, ...
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### 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 ...
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### How much electric energy is created by an 80kg man making a step at flat surface while walking at the normal speed (5km/h) [closed]

Even a rough approximation would be helpful. But of course a precise calculation would be great :). Thank you all in advance very much for your help! By the way - do you have any suggestion for ...
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### List of questions about charge, voltage, and capacitance

Let's just say you run a 5V current from the battery into a circuit. From what I understand, this means that I am essentially pushing high potential electrons into the circuit. These electrons would ...
284 views

### Forces on charges moving through battery

In the attachment, which comes from a text "Introduction to Electrodynamics" by Griffiths. There are two statements: "Within an ideal source of emf (resistenceless battery), the net force on the ...
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### What is voltage in a circuit?

What is voltage in a circuit? I know potential difference is the difference of potential energy of two points in a space affected by an electric field per unit charge. Why is there voltage in a ...
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### What exactly is a “volt”?

What exactly is a volt? So I Studied the chapter "electricity" in the month of April and got introduced to the concept of "volt". The concept was too unclear for me so I tried to ask some questions ...
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### How to find points with same potential while solving an equivalent resistance problem?

Lately, I've been reading about techniques to reduce networks and find their equivalent resistance/capacitance. While doing this, I came across the cube resistance problem and many other problems (eg. ...
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### Potential Difference

Ohm's law: $$V=IR$$ Here $I$ is the current in the circuit, which is equal to charge flowing per unit time. $R$ is the resistance offered. $V$ is potential difference. What's the physical ...
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### Is potential difference the difference in electric potential energy or electric potential?

Referencing the book Physics for Scientist and Engineers, Ninth Edition, the book says that "Potential Difference should not be confused with Difference in Potential Energy." I also reviewed several ...
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### Electric potential in a wire

I am slightly confused on the physics of direct electric circuits. Here is what I have been taught: Batteries (sources of emf) provide a constant potential difference between its terminals; Electrons ...
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### What is the difference between the potential difference and potential energy of an electron?

What is the difference between the potential difference and potential energy of an electron? Let's take an example the potential difference (PD) across a resistor. if there's a current flowing, the ...
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### Movement of charges in presence of electric potential difference

This might appear to be a bad question to some but i can't figure out the answer. While reading about an electric circuit, i found this on the web: Over the course of time, one could think of ...
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### Potential difference in a circuit of n cells = 0? How?

I was supposed to find the potential difference across any one cell in an arrangement consisting of n cells of EMF E connected in series in a closed circuit and internal resistance r. I proceeded by ...
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### Why the electric potential energy the charges carry in a electric circuit does not vary with its distance to the opposite terminal?

I understand that with wires assumed to be ideal, there is no resistance and subsequently no force acting on electrons, hence no work done and p.d. across any segment of wire. However, as the ...
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### Understanding electric field and potential inside an half-connected wire

Let's say we have a 9 V battery and a wire as shown in the image below: Let's assume H is the reference for measuring potential. I know the potential in F is 9 V, and I know the electric field in F ...
885 views

### Potential difference of conductor with induced load

If a metallic sphere is grounded and close to a positive charge q, it will be charged with -q. Let's say that the electrons will arrive through the grounding. This charge will cover the surface of the ...
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### At what distance is lightning dangerous for someone lying down?

My 8 yo child told me that they learned at school that they should lay down flat on the ground in case of lightning. I told him that the more correct position is crouching down with feet together, but ...
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### How do the electrons know the route? [duplicate]

I've learnt in classroom that the requirements for electrical current to flow in a circuit are as follows: there must be a closed conducting path between negative and positive terminals there must be ...
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### Why the electrons flow from higher potential to lower potential?

We know that every thing moves from a higher potential to lower potential. In fact we also studied in our textbooks that a charge travels from higher potential ie. Positive side to lower potential ie. ...
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### Potential in uniform fields

First in a book I found that the electric field strength $\mathrm{E}$ of a uniform electric field from a charged plate is equal to $\frac{q}{2\times \epsilon_0 \times S}$ where $q$ is the charge of ...