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Questions tagged [electricity]

The study of the presence and flow of electric charge. Charges, currents, fields, potentials.

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Electrostatics question inquiry [on hold]

The answer is C given that the left ball is positively charged. But since the sphere is heavily positively charged, shouldn’t the sphere repel the left positively charged ball rather than the left ...
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1answer
36 views

Stack/Chimney Effect: a physical explanation on how height of chimney affects $\Delta P$

A fellow engineer told me that there are greenhouses which exploit the stack effect, in order to cover some or all of their electrical energy needs. This is achieved by installing small electrical ...
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59 views

Idea for very lived energy source? [on hold]

I had an idea where you could build a device that could generate energy over a long period of time. my idea is that you could us alpha radiation, the most ionizing radiation, to ionize a material ...
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2answers
108 views

Current in infinitely long wire? [on hold]

Theoretically, suppose an infinite-length wire with completely no resistance (0Ω) connected to the terminals of a battery, and an electric lamp placed in the "center" of said wire. The question is: ...
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24 views

Hydrogen Sulfide New Superconductor? Is It Possible For Hydrogen Sulfide?

According to a very trusted science source : https://www.zmescience.com/science/news-science/superconductivity-artic-temperatures-05342/ There is now such thing as a Hydrogen Sulfide Superconductor ...
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14 views

Electric Charge and Electric Field [on hold]

A particle with positive charge Q is held at the origin. A second particle with positive charge q is fired at the first particle and follows a trajectory as shown in Figure 22-28. Is the angular ...
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2answers
49 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 ...
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15 views

Conductors and dielectrics [closed]

A parallel-plate capacitor is connected to a power supply that maintains a fixed potential difference between plates.If the sheet of dielectric is then slid between the plates What happens to i)the ...
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31 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
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Please help identify this physics apparatus!

This was my grandfather’s and have no idea what it is only that it is some piece of physics equipment! The main black cylinder doesn’t seem like it wants to rotate but not sure if it should?
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0answers
24 views

Contains Voltages and conductors [closed]

Can someone help me solve this physics problem? I'm having trouble understanding in our physics lesson and I'm confused on what is being asked here. And i'm also confused on what will happen to the ...
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1answer
36 views

Can lightning bend metal?

If lightning strikes a metal pole, will it bend because of the force exerted by Earth's magnetic field on the current?
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15 views

Circuits and potential difference

Is it possible to have a circuit in which the potential difference across a battery in the circuit is zero?if so,can you give an example if not.why?
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Electric force and charges [closed]

Four identical charges q are placed at the corners of square of side L. A) In a free body diagram, show all the forces that act on one of the charges. B) find the magnitude and direction of the total ...
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22 views

Application of Gauss's Law [closed]

A 9.60-mc point charge is at the centwr of a cube with sides of length 0.500 m. a.)What is the electric flux through one of the six faces of the cube?.b) How would your answer to part (a) charge if ...
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0answers
23 views

What is the connection between the nail, wrapping wire and the outlet? [duplicate]

A student attempted to cook a hotdog by inserting a nail into each end of the hot dog, wrapping a wire around each nail, and inserting the wires into a wall outlet. This cooked the hotdog, but it also ...
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2answers
18 views

What is the advantage of stacking the electrocytes? Of having the stacks side by side?

Electric rays (genus Torpedo) can deliver electric shocks to stun their prey and to discourage predators. The voltage is produced by thin, wafer￾like cells called electrocytes, each of which acts as a ...
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2answers
57 views

Why does the diameter of household wire affect the maximum safe current?

The greater the diameter of the wire used in household wiring, the greater the maximum current that can safely be carried by the wire. Why is this? Does the maximum safe current also depend on the ...
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0answers
34 views

Phenomenon called ”St. Elmo’s fire” [closed]

When a thunderstorm is approaching, sailors at sea sometimes observe a phenomenon called ”St. Elmo’s fire”, a bluish flickering light at the tips of masts. What causes this? Why does it occur at the ...
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2answers
67 views

Is there a fundamental efficiency limit for generators?

Im currently interested in the theoretical efficiency limit of a generator, ie any device transforming kinetic energy to electrical energy. In particular, id be interested in turbines, that convert ...
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0answers
16 views

Two conducting rings rolling on a conductive surface in uniform magnetic field [closed]

From what I understand about equipotential surfaces is that if two conductors are connected with each other with a conducting surface then the potential difference between any points is 0. If it is ...
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0answers
52 views

Electric Energy [closed]

A physics student attempted to cook a hotdog by inserting a nail into each end of the hot dog, wrapping a wire around each nail, and inserting the wires into a wall outlet. this cooked the hotdog, but ...
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2answers
48 views

What is it about a light bulb that makes the resistence greater as the voltage increases?

I have a question on one of my physics labs that I do not exactly know how to answer. Question: Is the resistance for larger voltages greater than, less than, or equal to the resistance at smaller ...
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15 views

A question on an AC Current calculation. [closed]

So I got this question and I'm not sure of my steps so here goes: If a 120V rms supply is used to charge a 10A DC device at 14V and the efficiency of the system is 70% then how much current is drawn ...
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0answers
16 views

What is the voltage breakdown of saw dust particle board?

I have done some testing for the electrical breakdown with the type of wood called particle board. But this particle board is made out of fine sawdust. So I guess what I’m asking is this. Question: ...
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2answers
17 views

Effect of electroplating on resistance

How will resistance of a wire be affected if I electroplate it with copper will it decrease ? And if yes then will the decrease be significant? I need to find a topic for my project I thought it might ...
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1answer
21 views

The direction of the electric field at a point on a diameter away from the center of a uniformly (positively) charged hemisphere

The answer is : perpendicular to the diameter. I don't understand how to arrive at that answer. I'm taking a high school physics course and have covered Electric field and Gauss's law for simple ...
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1answer
20 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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0answers
52 views

A difficult mix between thermodynamics and electricity [closed]

Consider the device in the image.The cylinder has dielectric walls which do not permit heat change between the gas that is inside and the exterior environment.The cap A of the cylinder and the piston ...
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3answers
37 views

Does a filament's resistance increase as current through it decreases?

I'm confused about resistance's relationship to current and power. Scenario: CIRCUIT A 10 V battery 100 W incandescent light bulb Calculate resistance: I = P/E I = 100/10 I = 10 amps R = E/I R = ...
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1answer
23 views

Electric flux and electric field lines [duplicate]

Why we draw finite electric field lines passing through a surface when we can draw infinite ? also why electric flux is proportional to the number of lines passing through a surface ? i am confused ...
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1answer
39 views

What is the equation for the electrical arc length of an arc that has been struck?

I have been experimenting with voltages at 2,320 volts AC. I am curious and haven’t found any equation to calculate the electrical arc distance that is drawn after striking an arc by touching the two ...
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1answer
29 views

Electric force between two parallel plates one of which got a rough surface

So if I have two parallel metal sheets separated by 0.1 meters with air as a dielectric with a breakdown strength of 3MV/m and I'm applying a voltage pulse that goes from 0 to 100kV in few ...
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0answers
15 views

Sparks from Metallic box hit by lightning

If a metal box of say 1 square foot was hit by lightning via a 60 meters AWG 6 wire suspended from a glider (or big kite) up the sky. What is the distance from the metal box when sparks of it can ...
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1answer
26 views

Electromagnetic induction by a coil

Moving magnet produces current in a coil and the galvanometer shows deflection because of the change in magnetic flux. What if the coil is moved why won't it produce an induced current?
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3answers
73 views

How much electricity can a kilo of electrons produce?

I know how stupid this question sounds. I heard my grandma say something close to it in a phrase "It's a 1000€ aircondition, it's not gonna consume 200 kilos of electricity !" Made total no sence ...
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2answers
69 views

Extreme high voltage path of least resistance changes?

In this video, there is an extremely high voltage being sent through a blank breadboard. The arcs go through different, seemingly random new paths. What causes this? How could you determine what the ...
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0answers
42 views

How dangerous is induction in my wires? [migrated]

I had to replace a cable going to a light switch. The cable was about $7m$ long and contained three ($1.5mm^2$) copper wires, with a distance of about $2mm$ between any two of them. Source One wire ...
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1answer
75 views

Are permanent magnets a relativistic effect?

The relationship between Electromagnetism and Special Relativity is something that always amazed me but I haven't fully understood yet. Misconceptions and contradictions seem to be widespreaded, and ...
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1answer
43 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
21 views

How to explain these observations on the first load, with two loads in series?

Recently I purchased the Snap Circuits Jr. kit and was working through the different projects with my daughter. We decided to connect two loads in series circuit, powered by the battery source. The ...
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0answers
20 views

What is the electrical resistivity of air during breakdown?

There is a well-documented theory for breakdown voltage vs pressure in the form of Paschen's law. But what is the trend of the electrical resistivity of air as a function of the electric field ...
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33 views

Capacitor open circuit voltage change with temperature

Given a charged, open circuit capacitor, and assuming leakage is negligible, does a change in temperature change the voltage? A capacitor's capacitance changes with temperature due to thermal ...
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0answers
20 views

Induced EMF on the secondary coil of a transformer

I am trying to understand which formula to use when calculating the induced EMF on the secondary coil of a transformer which takes into account the loss of magnetic flux due the separation of the ...
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3answers
83 views

Does touching the Live wire makes it neutral?

If I have two 'hot' wires connected to a source and a load, and one of the wire is connected to the ground, this wire is called the 'Neutral'. But what happens if instead of using an additional wire ...
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2answers
86 views

Good conductor of electricity and bad conductor of heat

I wonder, how a graphite can be a good conductor of electricity but at the same time, be a bad conductor of heat.?! As we know, a body conducting electrons are bound to produce heat by resistance, ...
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1answer
28 views

Heating effect of fast neutrons in Fast Breeder Reactors

Do fast neutrons play effective(meaningful) role in heating up the water in Fast Breeder Reactors? If so, how much do they?
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2answers
26 views

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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1answer
45 views

Electrified water from power lines

Isn't it water is a good conductor of electricity? How come you don't get shock standing understand a power line when it rains. Or specifically. Supposed the rain is continuous (or a building has ...
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2answers
91 views

In superconductivity, does the diameter of the cable affect the current?

In the water tank analogy below, the smaller diameter pipe (B2) will drain tank A slower than the larger diameter pipe (B1) We are told that resistance has this same effect on current the bigger the ...