Questions tagged [charge]

A fundamental physical property held by various particles, most notably electrons

Electric charge is a fundamental physical property of different particles. Each particle has a charge which is either positive, negative, or neutral (also called having no charge). Electrons have negative charge.

Charged particles exert a force on each other. Like charges repel, opposite charges attract.

The motion of charge is electric current. By convention, we refer to current as flowing in the direction positive charges are flowing. Since electrons have negative charge, electron flow is opposite from current flow. This has minimal significance for most purposes.

In some cases, an imaginary particle called a "hole" is posited. A hole has positive charge. In physical reality, a hole is the absence of an electron. It is sometimes useful to model this absence as a particle.

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Why is the Anode positive if Anions are negative...?

When I was younger I learned in Chemistry class that Anions were negatively charged and Cations were positively charged (Fun fact: I memorized this because anion sounds like onion which makes you cry and is therefore negative; while cation has cat…
HellaMad
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Why does electrical charge concentrate at sharp points?

Think of a metal object with one side round and the other side sharp. And we charge the metal either negatively or positively. Why is charge more concentrated at the sharp point? Why Don't electrons repel each other stronger at sharp point? So that…
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How to impart a charge on dust particles?

I am planning on building a simple electrostatic air filter, from scratch. From what I understand, the dust in the air is given a charge as it flows through an inlet section and is collected by mesh of opposite charge as the air flows out through an…
James
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Relationship between charge and electric potential

I'm reading about electricity on the Sparkfun website (https://learn.sparkfun.com/tutorials/what-is-electricity/electric-potential-energy), and I read the following: "At any point in an electric field the electric potential is the amount of electric…
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High input voltage charge pump

Related to my last question, I decided to go with a step-down charge pump to convert 5V to 35V down to 3.3V at 10mA, due to the smaller required component size. However, I can't find a single charge pump IC rated to go up to 35V. Does anyone have…
Thomas O
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how to charge a steel ball

I have a 2 mm radius steel ball and I want to charge it in a 0.025 Coulomb charge. Can I do that domestically or the charge is too high? And how can I do that assuming I don't have another conductive material that I know it's charge?
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Calculating charge when current is a piecewise function

The current is defined as follows:\$\$ \$ i=\begin{cases} 4 & 0 1 \\ \end{cases} \$ The goal is to calculate the charge from \$t=0\$ to \$t=2\$ s What I've tried: I've tried integrating both parts. \$\int…
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What happens if an object has a negative electrical charge and it is touched to an object with a neutral charge?

I am a beginner in this subject and trying to understand the basics. If I rub my feet on a carpet and pick up additional negative charge on my body and touch a neutrally charged object, say a piece of metal, will the excess electrons in my body not…
ABD
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How to calculate the total charge of a sphere which has a none uniform charge distribution?

If I am given a certain funciton which describes the volume charge density within the sphere with respect to the radius (ρ(r)),how can I calculate the total charge within the sphere.My idea was by calculating the total charge of many infinitesimally…
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Are the anodes and cathodes in a vacuum tube truly charged?

Are the anodes and cathodes in a vacuum tube truly charged? Can I treat them like any other charged object? also how can I calculate the charge? How would I calculate the alternating charge if it's ac?
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Calculating induced charge

Let's say I have a battery with V volts. A conductive material (Material A) is connected only to the battery's positive terminal. Material A is then connected to a second conductive material (Material B) that is not connected to anything. After…
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Why does this solution say that "the total charge is" \$\Delta q\$, when \$\Delta q\$ actually is the difference/change in charge?

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 1.5 Power and Energy gives the following example: Example 1.4 An energy source forces a constant current of 2 A for…
The Pointer
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Difference between charge-sharing and charge-redistrbution

I've come across these two phenonmenon in several places but I want to know - what's the difference between them in a general two capacitor circuit case (not related to SAR ADCs) Like if I have two unequally charged capacitors in parallel with a…
AlfroJang80
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The importance of knowing that charges only occur in nature as integral multiples

So I read the following about electric charge from Fundamentals of Electric Circuits (fifth edition) by Charles K. Alexander and Matthew N.O. Sadiku : "According to experimental observations, the only charges that occur in nature are integral…
DigiNin Gravy
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Find charge per unit length of conductors

Sorry if off-topic but I have a question in electrostatics. I didn't get any usefull answer at physics forums. The problem states: Three very long (theoretically infinite long) hollow cylindrical conductors, with radius a,b,c,(c>b>a) are in vacuum.…
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